Comment by nightpool

In which way is Facebook Container "stricter"? Are you aware of any potential third-party tracking vectors that Firefox does not currently mitigate, but Facebook Container does? The only possible difference I can see is that Facebook Container keeps sites "shared" via Facebook inside of the Facebook Container, so if you navigate from e.g. Facebook -> CNN, facebook can only see the history of CNN pages you've visited inside of the Facebook container. Otherwise, clicking on a share link from Facebook (with, e.g., a unique query parameter) would allow Facebook to correlate their CNN.com facebook cookie with their Facebook.com cookie, getting (retroactive) access to all of your CNN history. So maybe that's one reason to continue to use Facebook Container