I recently started using firefox and was very frustrated with how large the UI was, how it autofilled entire URLs while i was trying to search something, and how it changed my system's titlebar buttons (minimize, maximize, close) to windows ones when I changed the theme from the default. I just found out about about:config and was able to solve every major issue i had with firefox literally within minutes, so why do they hide most of the settings?
it makes way more sense to just put the settings in the settings menu. also, why hide the compact density option? on a 1920x1080 display the default is about an eighth of my screen, my taskbar is only like 60% of that. having tried a couple of firefox-based browsers, i can confidently say the only thing any of them do better (aside from telemetry that can be easily turned off) is their settings. why does firefox hide most of the settings?
Firefox is not the only browser that hide settings, i remember when opera used the konami code to unlock settings. I think it's just for poweruser since you are able to broke things with some of these settings.
since we're essentially down to chromium-based browsers and firefox. they all have 'hidden' settings.
A lot of the stuff in about:config is definitely more developer/power user stuff, but there are also a lot of things in there (like the ones I mentioned) that should be in the settings.