I like Ledger and Trezor. As far as I understand it, they do not store coins or tokens. Coins and tokens are stored in the chain. Ledger and Trezor are good for storing and using the Pkey.

Additional security is adding an additional security feature, so the pkey is not the only "central" security feature. Think decentalized.

"Why would you want an email ...": Well, you can have a special email just for that. You can have a free automated pgp-encrypted email (f. i. proton). You can change emails from time to time. The idea behind linking email and wallet is to have a second verification process. The email can also document the processes if you like that.

Mathematically the pkey is "kind of probably" safe. Emotionally it is not.

Bye.