No matter how you sync, a Keepass file is a file. I can't be logged out. It will still be on my phone if my house burns down. Every device it's synced to is an additional backup copy.

The Bitwarden client will sometimes log you out if something happens on the server side, which has the potential to make worst case recovery from annoying to impossible. The circular dependency of having my cloud backup password in the vault made me nervous.

Yes, you can back your vault up, but it's a manual step and likely to be forgotten.