If Mozilla released a separate passwords app so you could manage and access your passwords outside of Firefox I think the two would be more comparable. That would promote your passwords as part of your Mozilla account, not just Firefox.

Bitwarden excels here, and i think is the model to beat. However, Mozilla would have the advantage since their browser integration would essentially be built-in and first class.

Otherwise, unless you use Firefox exclusively for everything I just don't think a single browser is the right place to manage passwords. I would say that's true even for a broad audience, given the importance of passwords and security in the modern age.

Bitwarden is also nice in that you can "lock" access to your passwords while keeping the browser open. That way, for the 99% of the time you're just browsing the internet you essentially don't have access to all your passwords "open". The last time I looked at this I had to enter my master password on opening Firefox, even if I didn't need access to my passwords. That meant that "unlocking your vault" is essentially tied to opening the browser. That alone was enough for me to bail on it.