Re:“Invalid Username or Password”: a useless security measure
by layer8 on Wednesday November 23, 2022 @11:29AM
(#33721246)
The problem is if an account for that email already exists, see https://news.ycombinator.com/item?id=33720063.
So in the email you can include a link to optional account (username/password) creation.
And if you aren't sending an email, then the user has clearly decided not to create an account.