Seems like a good thing for founders, doesn't force them to quit school to start a funded startup. Especially for under-privileged youths who might not be able to miss a high paying job opportunity or have no income for months.
Seems like a bad signal for YC though - if you aren't committed enough to quit school or at the very least reject job offers and do your startup anyway - feels like you might not be committed enough to do what it takes?
But if anyone does, YC knows how to pick founders with the right mindset.
I think there is some risk of that. But commitment isn't static. A lot of incredible companies started with founders who were just toying with an idea and weren't committed at all, then they became more committed over time as things started to work.