Mail.ru is more than real, there is just a trend to move away from passwords because they are not secure when used by ordinary people and can be stolen with a keylogger. So Russian services move to SMS codes, mobile apps or government services for authorization. Also it is a legal requirement to implement a system that doesn't allow anonymous registration, not linked to real identity.
> Please enter the phone number you'll use to sign in to Mail instead of a password. This is more secure.