They should because it would be the right thing to do... and Firefox is more popular then the Tor browser, so it would help spread Tor adoption... a lot of people don't understand the benefits of hiding your IP... so they aren't going to download the Tor browser
It is for me. Tor runs as a daemon, then I have my Firefox proxy settings to always hit Tor.
Onion addresses work, and Firefox refuses to connect if the Tor daemon isn't running.
Paired with Firefox actually honoring my requests to purge all information upon exit (instead of chrome only "kind of" doing it), it certainly works out quite well for me.
It is based on Firefox but it is not Firefox... but anyways, unlike the Tor browser, maybe Firefox should not use Tor in regular mode (only in incognito).
