Not 100% sure when Apple implemented this,
but now if you want to type a text on Apple Watch you can select “type on the iPhone” option.
When an Apple Watch app (e.g. stand alone, as “Bring!” App) wants a user to log in, user can type a username/password on the iPhone and it will be sent/handoff to Apple Watch:
The iPhone recognizes the password field and offers to use a password manager (Bitwarden) to fill the password.
When I search for an entry/website for the autofill (no option to copy username/password) and select/click on my entry…
I expect: password pasted to the Handoff field.
What happens: nothing/bitwarden closes.
The only step to reproduce this:
install “bring!” app on the apple watch and try logging in by selecting "input username/password from/on iPhone.