Anything that has Oauth2 integration with Github, Google, Facebook, etc. out of the box is going to win this by a country mile. That's by far the most annoying thing about setting up any website that has user accounts in my experience.
Plus, it offers very little convenience for users vs just using a password manager. I realize figuring out the right bcrypt/datastore setup is kind of annoying, not to mention opening you up to liability, but it's always been worth it to me in the past.
One additional benefit to having OAuth2 support though is that you can easily set up SSO if needed (and you don't care about SAML or other SSO protocols). For me personally this will be useful for an NGO that I'm running where we have Google Workspace effectively serving as a Single Sign On server.
It definitely does - the sign-up process is much quicker with oath2.
Once you're signed up, sure.