Another (is this bogus?) reason for not applying is I am not in the US and would prefer not to migrate there due to family. Can a founder do YC with minimal time in USA or even do it remotely.
But e.g. there was a great team in our batch (W24) with very young kids who flew to SF for in-person events. Some people were unable to come to the US (visa issues) that took part remotely.
No requirement to intend to stay in the US – many foreign teams heading back, but many more haven chosen to stay in SF on O1 and other visas (YC helps with this).
I think YC admissions see the intention to be based in SF as a net positive, because SF is in most situations the very best place to start a startup (regardless of YC).
But I believe you do need to be there with your co-founders for 3 months.
And if you can't manage that then running a VC backed startup isn't what you should do.
Because you will need to visit customers and it's often not feasible to just fly to/from constantly.