Because if you don't want to, it'll get in your way every time you try to use your actual passkey. Oh right, I forgot they added an option - now it just gets in your way every time you try to use your actual passkey on a new device.
I love Bitwarden but they still don’t support that on mobile phones.
I think it's very close to landing into the release version. I've seen people discuss it working in the testflight/beta release on iOS