[toyg]

The main difference is that profiles allow for different extensions to be enabled. You effectively get completely different browsers. The price for that power is a bit of IT geekery - if used regularly, you'll need either a bookmark to about:profiles or a desktop shortcut pointing to Firefox.exe -P yourProfile.

I mostly use containers for everyday work, but when a site looks borked (which typically happens because of strict ad-blocking extensions doing their job), I temporarily switch to my "unprotected" profile that has no ad-blocking whatsoever.

(And also when I test new extensions I build, but that's a very niche use case.)