It's sort of like a daycare, sort of like a kennel, sort of like a resort kids' club, sort of like summer camp. Some place you can dump your kids off for a couple of days while you go on vacation without them.
Sure, lots of folks are lucky enough to have grandparents who can watch the kids. But lots of people don't, and they want to get away from their kids, too. Even more, because they haven't been able to for years.