The browser built-in options are too limited. I want to do these things:
- Use multiple browsers
- Sync even if <browser vendor> screws you over and terminates your account
- Store things other than passwords. Credit card numbers, PGP keys, SSH keypairs, etc
- Backup the database to my own storage
Export/import is not enough. If I use Chrome, then import to FF, then add a password in FF; now Chrome is missing some data. You need to be able to sync, not just import.