Quite honestly YC is the only one of these kinds of ventures that I trust. And even in the case of YC, if I were to advise a budding pair of young entrepreneurs, I'd tell them to move back in with their parents for a year, get a low skill but high paying job to give them sustenance money (e.g., bartend or barista), and focus on implementing their idea. There are nice YC value adds like being introduced to influential folks. But part of being a business person is finding a way to get to these folks anyway. Why pay for this service when you can get them for free?

So many startup folks are attracted to these kinds of programs because I think they mimic the illusion of safety that school offered. You have to be "accepted" and it's not a venture but a "program". Everything is geared towards creating this sense of safety without pointing out you are giving up a lot for it. Know why these programs want to save you the hassle of doing your own incorporation paperwork that took me a day to figure out when I was a teenager? Because they have to put clauses in that will help them, not you.

Again, I'm not saying these ventures are sinister. But you can get by without them and in fact may become a better business person for it.