> You can back up all Telegram chats including Media, of course this doesn't replace email, but the difference is just a client to parse the data and log it in a message style front end.

While this is true, there's no automatic process and it's limited to the desktop client. Email is much more convenient because of this. I can't "forget" to backup my emails for the past month or year. I know they'll be on my email server until I delete them.