I have seen them out in the real world a couple of times. Only, thank God, on women under the age of twenty-five. They all had perfectly good figures and they all looked terrible in these leggings.
A man might disagree, I don't know. Maybe guys like the ten-ton-sausage-stuffed-in-latex look. Perhaps to them it screams S-E-X!!!! But if you're over twenty-five (and therefore expected to have some sense) and you want to look like you have some class, don't wear these.
Maybe if you're emaciated and trying to look like you aren't then they could work.
If you really must wear hideous leggings this style is surprisingly more flattering to the non-emaciated figure:
I saw a regular woman (probably in her thirties) wearing these the other day and, while really not to my taste, they were in fact flattering.
One more thing about leggings: wear a long top with them. Really, cover your butt and your crotch. I don't care what the other girls are doing. You'll thank me when you see photos of yourself a few years later. Or you'll wish you'd listened to me.
Yes, I do know this from experience.