> site-specific container assignments

This is (or was, before I switched to Vivaldi) the killer feature of Firefox containers for me. I could banish certain tracking-heavy sites to their own containers so that they could only track where I've been on their own properties and not across the whole web. (Without having to remember to switch to their containers beforehand.) So I guess if I go back to Firefox, I'll still have to use the extension.

And maybe I'm misremembering, but I thought that containers did more than just separate the cookie jars? I really like using Vivaldi/Chrome's separate profiles because then I can have separate extensions/settings/polices/etc for each one. Some sites don't get along with certain extensions.