Firefox adds tracking protection by default

Of course - even without cookies, they can track visits by IP address and whatever other bits of entropy they can get their hands on, in addition to causing useless traffic. So blocking known trackers is of course a good thing. But blacklists will never catch everything, so what I really meant was placing whatever escapes the filters in an empty session.

That's what I do right now with a combination of Firefox' built-in tracker blocking, uBlock Origin and Temporary Containers (and Containerise for the few sites I actually want to keep in a persistent session). That system works, but obviously it requires manual setup, so I appreciate them moving to protecting privacy better by default. Also, it does have a few rough edges here and there, mostly related to using containers in a somewhat unintended way (e.g. opening a new container, even automatically, forces the creation of a new tab).