The entire point of these hosted password services is that they are a turnkey solution - I could give them to my mom, who knows nothing about technology, and trust that they work. I like using a turnkey solution myself even though I could self-host because I don't want to spend brain cycles on solving the "syncing passwords across multiple devices" issue.
I don't quite understand why Bitwarden even needs to have you login in order to access the passwords. Surely you could just have the salted+hashed passwords on device, and Bitwarden just syncs that data from device to device. If you work in an organization and need to revoke access, just change the password. No need to manage whether or not someone is logged in to Bitwarden.