I assume it's for the same reason that people use services like Auth0 -- they don't want to waste development time programming all the fringe cases for authenti

I assume it's for the same reason that people use services like Auth0 -- they don't want to waste development time programming all the fringe cases for authentication, when all they really care about is logging a user in and trusting that they are who they say they are. Some benefits: * Quicker to MVP * Don't have to rewrite AuthX for each platform (web, iOS, Android, etc) * Less worrying about the various permutations of 2-factor across all the applicable auth types (username, email, oauth, LDAP) * Not having to figure out how to federate identity * Not wanting the burden of GDPR/Privacy compliance in-app etc.