Chrome profiles, for example, isolates browser extensions, bookmarks, browser settings, and saved passwords. I haven't used Firefox containers yet but, based on the docs and demo I watched, it doesn't look like it has that level of isolation.

If you want to have different preferences, bookmarks, extensions etc. set for different profiles.

For example, I might want to allow 3rd party cookies on a work profile but not on a personal profile.

Firefox history is shared among all container tabs. While some of my usage is automatically governed, not all is, hence why I moved to profiles for certain needs for separation