The email is ultimately the second factor that lets you make important changes to the account in many cases. For example, changing your password. It's more important than the password in nearly every security critical account I have.
This is not always the case. Reddit sometimes locks the account until you verify it or reset the password by email. Happened with my email pointed at a .tk domain and I had to call freenom a bunch to get the domain back.
Since the last few years Reddit has basically just become Facebook 2.0 and it's not even worth using at all. They probably got acquired by private equity or something.