I'll start with the most important first
1. When you take YC money you get to pay yourself. You wont be paying yourself FAANG money (if that's still achievable nowadays who knows) but you are paying yourself to build a company you own the majority of. So yes, they want you to dig to the center of the earth to find gold but you are being paid to do so.
2. I don't think starting a niche startup is meaningfully easier than starting a startup seeking uber growth. While a tech startup might require more up front knowledge I don't think startup ceos are working harder than the baker that's waking up at 4 am every day.
3. YC has a very good success rate and I think it's related to services they provide founders and the network.
I think if your business falls into the category of hyperscale startup and you are a first time founder I really think YC is worth it. They seem to have a system that works.