Yeah, I would say they're somewhat popular as an alternative to swings. They're good exercise if you're on for more than a few minutes since they can really work the quads. They can be fun too! At least that's what my daughter and her friends say.
Friends across town have one that did in fact "blow away" a few years back, damaging part of a wood fence and crashing into their neighbour's house. So I figured it'd be a good idea to never know what that's like.