Selling me on Tree Style Tabs -- and thereby an analysis of the downsides I see to the specific browser/extension configuration I need to have to get such a feature in practice today -- seems very unrelated to why anyone uses or wants tab groups ;P. I have access to tab groups and am not using them, because I don't understand the workflow for them, and all the demos feel contrived: users for whom supposedly a mere five or six tabs are so many they need to be organized into groups.

(FWIW, it is certainly highly related to why all of these users aren't satisfied by using an existing extension that implements tab groups: most of the reasons people describe also apply to why I am happier figuring out how to live without an extension for this. I personally believe it would behoove Firefox to lean heavily into being the one truly hackable customizable browser--steering towards things Chrome would balk at--but they have been running in the other direction now for many years and I am sad.)

As I said: I would definitely support any of these browsers implementing native "tree style tabs", but I don't (at least, yet) understand the workflow people are using for "tab groups" a la Chrome (the feature in question on this post that people want Firefox to integrate). I do want to understand, though! I legitimately am curious how people are concretely using tab groups, as the feature doesn't make sense to me currently but apparently a lot of people want it...