Some sort of email is absolutely necessary though. Preferably confirmation before creating the account, but I know of several that do this instead of confirmation - because someone else used my email address.
Yes, the conventional pattern seems to be a short email confirming your address and your intention to sign up, followed by the longer “onboarding” email after you confirm. Some commenters here are saying that these are the same thing and that I’m wrong. But it’s the onboarding email that I’m saying is superfluous, not the confirmation email.