The problem is they lose their email address, which is tied to just about every digital account they have. Losing your email can royally fuck you. Many sites send an email to the old email of you try to change it, so you’ll have to get in touch with support to get it changed, and then support will want proof it’s your account somehow, and the whole process is gonna take days or weeks to fix all your accounts. God help you if you forgot any passwords because now you can’t login or even reset the password since that goes through email.