[posix_me_less]

Yes it has benefits but also drawbacks; I don't like the tradeoff. You have to give the password manager too great capabilities to achieve the autovalidation+autofill. Maybe if you check and compile the password manager yourself.

Also automating the process entirely means the login process can happen and succeed (or fail and disclose the password to attacker) without the knowledge of the human.

I don't have time for that, so I just run both browser and password manager isolated and copy and paste the password.