I mean, it is additional work. Not only do you need to store the emails/passwords securely, which while it isn't _that_ hard, it is a needed consideration, but you also need to now:

- provide a password reset service

- find a way to send emails to this many people for low cost, it is a free service after all, so all of the confirmation/reset emails are an additional cost

- etc

If you store an email, you're liable for GDPR controls, IIRC. Why expose yourself to that liability if you don't need to?

It'd be nice to have a no-login localstorage-based option. I guess you wouldn't get on the leaderboard, but does anything else need an identity?

ask for a refund

It would be cool if auth0 (https://auth0.com/) would offer free usage of their service, given the fact that they would only use basic features.