You can judge for yourself by typing 'firefox -P -no-remote'. Right there, having to use the terminal , has already made it more clunkier than Chromium's solution. Admittedly, Firefox profiles are clunkier to launch & manage - like a hidden feature that has rebuffed all my attempts to streamline their management, as if by design. This can be remedied by use of desktop shortcuts (You can create separate shortcuts for different profiles) but then you have to also deal with the idiosyncrasies of your Desktop Environment (Gnome in my case :/) .
Once its launched its pretty much like running to separate firefox instances in your system with separate bookmarks, histories, settings, addons - like in Chrome. So it is a lot more heavier than containers as a result. Which is why i think the 2 functionalities shouldn't me unified like people in the comments seem to be asking. Similar to Threads vs processes. We need both.
Either way my point stands. Firefox containers aren't profiles and imo shouldn't replace them. They should make profiles more user-accessible, but both solutions should exist simultaneously. If anything, effective use of containers requires more advanced knowledge & awareness making it more suitaed for advanced users.
