Great idea, lazy execution.
Often fails to contain certain sites in their containers, popup for confirming a site be exclusively handled in given container sometimes unusable. Containers are a single flat list.
All that is minor, for an official addon it cannot sync settings, and settings are partially lost when disabled. Sites contained in default containers will be remembered, custom containers permanently lost.
If you are going to delete everything on disable (not remove), for any reason, at-least be thorough.

TLDR: Bare minimum functionality, still buggy. Is being an example an excuse for being poorly done?