I don't quite see them that way either, but, I further see tab grouping, tab hiding and profile groups as three separate parts of the same overall feature. And Simple Tab Groups directly supported Containers since day 1, so I personally always really found this distinction a bit more lexical than practical.
I absolutely love the hiding feature and find Containers incomplete without them. What's the point of switching context if the context is still visible there at all times? At that point, let me just use a different User. And I'd find Simple Tab Groups weirdly incomplete as well if they insisted on hiding tabs but not providing Container functionality. Because tab groups with hiding don't feel "ephemeral" enough. Takes too long to make a group, and the interface changes too much when jumping around. That dissuades me from going on tangents online and then grouping that tangent and keeping it on the side temporarily. Chrome's approach is better for that latter thing.
I want something in between. Something that let's you see all groups on a single bar or on a tree bar, and then further groups that can be containers and switch the bar. Chrome was close with their group save+hide feature, but they eat into the bookmarks bar with no options about where.
I'm not talking about Tab Containers. I don't need to segregate sessions/accounts or such.
Tab Groups is a way to be able to swap sets of tabs within a window. I can have groups for each of projects A, B, and C. Each project group can have a couple dozen tabs. When I switch groups, I only see the tabs for that group. I alternate among several projects each day and need to keep the pages live. Without groups, it is impossible to manage all of the tabs.
