MILWAUKEE, Wis. — The last time I was in New York, I was on foot and grateful for sidewalk sheds.

I understand why New Yorkers don’t like them: It’s dingy under scaffolds. With some 3,300 of them around Manhattan alone, wooden tunnels get tedious. But it was raining, my head was wet, my shoes were sodden, and I was wishing the sheds could cover crosswalks, too.

What I really wished for was a skywalk. These are an anathema in New York, I know. There are apparently some at Hunter College, but otherwise not much, not even nearby: Hartford, Conn., has been ripping out its aborted system. Hoboken city planners made a point of banning them. Newark planners want to. Besides, they’re unfashionable. “Everyone knows it’s a mistake,” one planner in Charlotte, N.C., said of that city’s system. A couple years back, Dallas’s mayor said she’d as soon plug her city’s tunnels — same idea, minus 35 feet — with concrete. Urban planners hate them, saying they pull people off the street.

This enmity from the profession that gave us housing projects and East Berlin should be a signal that skywalks have something going for them. In some places, they work.

Especially in Minneapolis. It has, easily, the largest skywalk network in the country. It gets used. “When it’s this cold, it’s kind of a no-brainer,” says Minneapolitan Peter Bruce, who surmises that in winter, the city’s 80-block system induces people to stroll. When we spoke, the temperature was about 6 degrees below zero.

Mr. Bruce is a pedestrian consultant and planner, perhaps the only man in his profession to like skywalks. He concedes Minneapolis’s system has led to emptier streets. Still, for a lot of people on foot, they work.

There’s the weather, obviously, and not just winter. Minneapolis summers get steamy. It rains. Yet a thunderstorm didn’t stop Todd Klingel, head of the local chamber of commerce, from walking eight blocks to City Hall the day before I talked to him last July — dry, thanks to skywalks. “People can’t get enough of them,” he said.

They let you move faster, since you’re not waiting at corners for walk lights. An you walk farther because of them, says Mr. Bruce. He’s measured it: People are willing to walk an average of five blocks from parking to destination by skywalk, three blocks by street.

They’re good for retail, too, says Mr. Bruce — it’s just one floor higher than expected. Downtown Minneapolis has lost some national chains lately, but as more residents move in, other stores and nightlife follow, and the downtown remains healthier than those in comparable cities. Still, even in Minneapolis, skywalks have critics. These take a normative tone.

A couple of big-name planners were invited in last fall and told the city to rip out skywalks. “They suck the public life out of the city,” said Gil Penalosa, a Colombian-Canadian bike-trail guru, who founded and now heads Walk & Bike for Life, a nonprofit dedicated to promoting recreational trails and pedestrianism.

His statement presumes that life is public only if it’s spent dodging bike messengers and getting hit up by street-side panhandlers. Mr. Klingel points out that it’s actually much easier to run into acquaintances in a skywalk than from opposite sides of a busy street, and it’s easier to chat if your flesh isn’t freezing.

Other critics mock skywalks as “gerbil trails.” Note the implication that users don’t choose them rationally, that the tubes literally sucked them against their will into 70-degree comfort. It’s as if elite opinion thinks that having streets is the real point of a downtown and that human preference is secondary.

One essayist repeated some of this routine cant in a local paper the other day. Refreshingly, he got a flurry of online pushback from actual downtowners.

This too, like the enmity of the planners, is a signal. Keep it quiet, but in a way, Minneapolis’s skywalks can be libertarian.

For one, they’re privately owned. They cost a million bucks each, but it’s not tax money — developers fund them. Critics don’t like this, since owners can keep out troublemakers. Doesn’t do you much good to block a sidewalk with your protest if people can pass right overhead and ignore you.

Better yet, on a skywalk system as connected as Minneapolis’s, you can go anywhere. Don’t underestimate this. The latest panacea for downtowns is to install a trolley — one-car “circulators” to trundle you from work to lunch to store, if you’ve got patience and you’re going the approved direction.

Skywalks, by contrast, are transportation without mass. You can walk when and where you damned well please. They work like freeways for pedestrians. No wonder people who want to tell you where to go don’t like them.

They keep you out of the way of cars, too. One of the great excuses city planners have used for years to impede driving is that pedestrians and “car-friendly” cities don’t mix. Put pedestrians and cars on separate planes, however, and there’s one less reason to harass drivers. Zero-sum thinking loses; freedom wins.

Not that any of this means New York should build a skywalk system, least of all to please soggy visitors. Minneapolis didn’t set out to build a network, which grew organically from landlords’ attempts to make life convenient for tenants. Its success could be an irreplicable accident. Still, if sidewalk sheds are the best that Manhattan can offer by way of weatherproofing, one can think fondly of gerbil tubes.

Mr. McIlheran is a columnist for the Milwaukee Journal Sentinel.