The issue with the native Firefox is that it lacks a bunch of codecs, that are non-free. To solve this, you either have to
Layer the codecs from third-party repos like RPM Fusion
Install the Flathub version of Firefox
I personally don’t want to alter the system image, so I would like to use the Flathub version of Firefox. But then you have two indistinguishable versions of Firefox installed. To solve this, you have to override-remove the Firefox package from the system image, which requires the terminal, a reboot and is just less convenient (more so for new users of course). Both solutions really aren’t ideal, and this issue would be solved if Firefox was shipped as a Flatpak instead. There is even a Flatpak version in the Fedora Flatpak remote, so why is it still shipped as native?
It basically boils down to the same reason why the rpm version of Firefox lacks the codecs - Fedora can’t ship those bundled with the operating system. Having the Flathub version installed by default would also violate that policy.
I think there was some discussion about not having Firefox installed at all - with the assumption that people would install from Flathub and won’t have to deal with the override remove step. But the problem with that is you wouldn’t have a major main web browser installed at all out-of-the-box (alternative would be to have something like Gnome Web installed by default, but also could result in a bad out-of-the-box experience).
I’m not saying to bundle the Flathub version. The Flatpak version but from the Fedora Flatpak remote should be shipped. This Flatpak is built the same way as the RPM. Yes, this means the codecs are still missing, but at least it’s easier to remove/replace.
AFAIK the reason the Flatpak isn’t preferred is because it cannot talk to the session bus and install GNOME extensions when you navigate to extensions.gnome.org
Once the Flatpak can do it, either through a new portal or tweaking its permission, I think Silverblue will switch over to using it instead of the RPM.
EDIT: not only for GNOME extensions, but the Flatpak version might cause issues with some passwords manager that communicate through DBus.
FWIW: Extension Manager (not to be confused with the official GNOME “Extensions” app) is amazing. It can download extensions directly from extensions.gnome.org and enable, disable, and configure extensions too.
It’s a much better experience than using a browser.
I can’t imagine running Silverblue without a few layered packages. I do have RPM Fusion enabled and have all the codecs needed for multimedia in Firefox.
I could probably be doing a little more in Toolbox containers, but I still am doing a lot.
Even my main browser, which is Vivaldi, is not available in Flatpak, so right out of the box I’m layering a huge package.