I've been using the built-in Containers in the Nightly browser since they first became available. Admittedly they are a power-user feature or for those that are vigilant about privacy/tracking.
I recently switched to this extension (over just the builtin version) to get the "Always open in container" feature which is pretty much indispensable due to external apps firing browser links (slack, email).
I wish there was regex/pattern matching support and literally any interface at all to see existing settings. The CookieAutoDelete extension has a great UI for managing cookie regex settings per individual containers - please implement something similar for this extension!