I use this in concert with the Multi-Account Containers[1] Add-on. I create names containers for things where I need persistence (“work” “personal” “LinkedIn”) and then everything else is isolated by default.
The main challenges are:
1) I have complex rules defining a whitelist on Temporary Containers. I have to sync this manually with setting import/export because Firefox Sync doesn’t handle this for you
2) Multi-Account Containers doesn’t expose its settings AT ALL, so I’m constantly hitting unnecessary “always open site.com in Personal container?” modals.
[0] https://addons.mozilla.org/en-US/firefox/addon/temporary-con...
[1] https://addons.mozilla.org/en-US/firefox/addon/multi-account...