I think they are semi popular. I absolutely love when I see teams with buns or braids. That says athlete far more to me than giant ponies. We want our kids to be taken seriously as athletes, let’s let them look the part. That said, my kid wears one. She has super curly hair and our gym has a straight hair policy (which really frustrates me, because I don’t like the message it sends to those who don’t fit the mold). Heat straightening her hair will damage it and even when I do, it makes it so long, it’s a lot of hair. A fake pony makes it easier. It gives her an awful headache, though, and if she was just allowed to be her natural, beautiful self, this would all be avoided. (Kind of a touchy subject for me, lol)