as long as you have one working device all will be OK. Either you scan the QR code shown by the website. or if you did login to Chrome with google account then desktop or laptop will just sign you -friction less. Same with iCloud account.

If you browser vendor has implemented passkey then all good.

Most things are built for the majority users. Most don't change. Most don't debate browser wars in hn. Life is like that.

For Wii etc. You just scan the QR code shown in the TV interface. all just works.

Yes, if you want 100% privacy and will do only your own dovecot server then it is not for you.