Storing 2FA codes is just the beginning. Bitwarden aims to add defense in depth to authentication.
Bitwarden Authenticator is a standalone app that is available for everyone, even non-Bitwarden customers.
In its current release, Bitwarden Authenticator generates time-based one-time passwords (TOTP) for users who want to add an extra layer of 2FA security to their logins.
There is a comprehensive roadmap planned with additional functionality.
it's basically just a shared random number generator on a timer (it's slightly smarter than that but that's the gist), so as long as you know the start time, the current time and the starting point for the RNG, both parties can get the same result without having to ever communicate