ID an password for a log in

Why is it the only way to continue a game is if you are connected on face book ?
Why can’t we have an id or name an a password .
This way all players can stay in the same game that they are playing,
If thé device used dies we can’t access the same game we have to start all over again.
This is unfair,
Please have it that we have an id an password
Thank you