The new flat-shoe emoji more accurately reflects my own footwear choices, too. I was recently getting dressed for a full day that involved writing at a women’s co-working space, a book party and dinner. I pulled on jeans and a top with feather-trimmed sleeves —comfortable enough to hunch over my laptop but sophisticated enough for a cocktail party. For such a schedule, I’d normally wear flats and stuff a pair of Manolo Blahnik BB pumps in my tote for later. But that day I hesitated: Why lug around stilettos that would bulk up my bag and then force me to teeter uncomfortably, when my Le Monde Beryl black velvet slides are just as lovely? I decided to put my (flat) foot down.

Brands are offering a wider variety of flats than ever, elevating what was once a casual work alternative or a commuting shoe to one that’s acceptable for more formal social occasions. According to NPD Retail Tracking Service, last year U.S. high-heel sales dropped 11% over 2016. Meanwhile, the selection of chic flats has become extraordinarily rich and varied. Whereas once vertiginous heels were the obligatory choice for events like weddings or panel presentations, today a dressed-up flat like the satin Balenciaga Slash slide fits in just fine. “Designers have been looking at bringing in more fashion, more trend, more design into a flat so it doesn’t look like a basic but it becomes a special option,” said Roopal Patel, fashion director of Saks Fifth Avenue. Flats are no longer the sad, casual Jan Brady to Marcia’s superior heel; they can be equally fabulous, and comfortable to boot.

High heels originated as a way to help 10th-century Persian soldiers secure their feet in stirrups, before becoming the preferred shoe for 16th-century male European aristocrats eager to look taller and more formidable. Women soon adopted the style, and in modern times heels became inextricably linked with femininity. Like its early male adopters, I appreciate how a heel provides a lift. At 5’3” (and a half!), I welcome any added height. Still, though a handsome pump has always made me feel polished and powerful, I’m learning that the right flat shoe can do the same.

“Women have always been wearing flats,” said Ms. Patel. “But what we’re starting to see is women wearing them from the minute they leave the house to the minute they come home. There is no shoe change any more.” Lily Hanbury, co-founder of Le Monde Beryl shoes, argued that your footwear “should be chic enough to take you to anything you’re going to that day.” Ms. Hanbury launched her signature flat based on a traditional Venetian slipper in 2016, ideal for busy, style-minded women.

We’re spending more time than ever on our feet these days, or at least being urged to. As standing desks prevail and Fitbits bully us to achieve 10,000 steps a day, comfortable footwear holds new allure. “What we’re seeing in the past few years is that women are more conscious of being healthful when it comes to their feet,” explained Dr. Neal Blitz, a podiatrist with offices in New York City and Beverly Hills, Calif., whose website calls him “The Bunion King of New York.” “Women just want to be active,” he said. “It’s not just about looking good in heels any more.” Shoe designer Tabitha Simmons, who counts her Hermione Mary Jane flats among her best-selling styles, would agree: “Everyone was tottering around on platforms for such a long time that it swung the opposite way, and women started wearing more wearable footwear.”

Dress codes have also shifted in the age of #MeToo; when you’re wearing heels, it’s hard to lean in without toppling over. In 2016 when then-27-year-old Nicola Thorp reported for a temp job at PricewaterhouseCoopers in London, her supervisor told her heels were mandatory. After being asked to leave, Ms. Thorp started a petition protesting such archaic dress codes, which was investigated by two Parliament committees. The outcome: The temp agency Portico that demanded heels changed its rules, and calls were made for tougher laws against dress discrimination.

Shipley Salewski, 39, a San Francisco-based educator and consultant, recently stopped wearing heels to meetings of the mostly male charity board she chairs, replacing them with a rotation of dressy flats including magenta satin Delpozo mules and sparkly Malone Soulier ballerinas. “The flats I wear in that professional setting are definitely elevated flats, they’re not boring flats. That’s a distinction. I like beautiful things, I like to look like I tried and I also like to not fall over.”

As Ms. Salewski found, you needn’t look dowdy in flats or like you forgot to switch into heels. While knee-length skirts look a smidgen too modest with flats, above-the-knee hemlines are charmingly cheeky. Opt for an ankle-cropped, slim style of pants; long, loose trousers double as a Swiffer duster. If you wear Mary Janes forgo the headband (too close to Eloise from the children’s books); if you wear ballet slippers don’t pull your hair into a bun (too on the nose).

Early in my career, an impeccably coiffed veteran colleague told me menacingly that she’d never be caught dead toting flats in her bag. A bit hyperbolic, perhaps, but I agree that carrying two pairs of shoes appears indecisive and unwieldy, so I’ve stopped throwing heels in my tote. When I wore my Le Monde Beryl flats on that jam-packed day, I was properly attired for the cocktail party but hit my 10,000-step goal on my way there, and didn’t teeter on a single cobblestone. I used to be head over heels for heels, but now I’m just over heels.

An Argument For Elevation

In which a confirmed stiletto-lover flatly refuses to change her ways

ABANDON MY HIGH heels? Not now, not ever. Tout the comfort of flats all you’d like, but I refuse to relinquish the power, stature, and self-assurance my spikes afford me as a concession to “practicality.” Who has ever aspired to be practical?

Over the last decade or so, I’ve amassed a small arsenal of towering shoes, their heels starting at 4 inches high. Each morning, I delight in surveying my cache and selecting my daily armor. No, I do not wear heels to attract the male gaze—anyone who’s seen my wardrobe of black tulle cocoons and conceptual, three-armed dresses can attest to that. Rather, my heels provide a mental and physical boost that makes me feel invincible.

I’m not alone in my adoration of elevated footwear. “I feel rather dowdy and frumpy in invisible flats,” said Linda Fargo, Bergdorf Goodman’s SVP of Fashion Office and Store Presentation. “Heels, even an inch, ‘lift’ me up.” Dianne LaPointe Rudow, the director of the Zweig Family Center for Living Donation at Mount Sinai, wears them at least four days a week. “I’m short, so I like to be able to see eye to eye with my colleagues. And just because I’m in a position of power doesn’t mean I have to compromise—women can be smart, successful, and feminine.”

Many have suggested that men invented heels to sexualize women and hold us back. That’s not strictly true, as heels’ origins as 10th-century equestrian wear prove. And while yes, heels are associated with erotic femininity (and so what?), Nancy Pelosi was no man’s object when she wore four-inch blue suede stilettos last February to deliver a commanding, eight-hour, filibuster-style speech in defense of DACA.

“I love high heels because they give you confidence—they give you an attitude, a way of walking, standing, and even sitting. You feel tougher and sexier,” said Carine Roitfeld, editor in chief of CR Fashion Book. Ms. Fargo agreed: “Clothing and shoes are more than just a surface expression. We internalize what we’re wearing and see ourselves differently, but to each her own. I’m more of the ilk of effort. Effortless, easy style? I can’t relate.” Indeed. Why be effortless when you could be fabulous?

—Katharine K. Zarrella