While it seems time-saving, I don't think putting all your eggs in one basket is a good idea when it comes to interviewing. If you bomb the interview (it can happen to great engineers), then you've effectively shut yourself out of every YC company? I'd much rather interview 5 times and be 99% sure I'll get one, than go all or nothing and potentially get screwed.
It's more like "set your budgets accordingly". I run a couple sites there and only once I hit one quota limit for a site I did not set a budget and that exceeded the free tier bandwidth limit. I like it specially for students because it encourages good practices.