Full disclosure: I miss Tab Groups! Like, REALLY miss them!

That being said, I've learned to live without them. Multi-Containers (from what I understand) may well supplant and/or replace Tab Groups some day, but until then the functionality it brings surpasses what Tab Groups originally did.

Placing websites in specific containers allows for multiple sessions within the same window, making it much easier to switch between multiple accounts without any complicated fiddling here, there, and everywhere; and as someone who maintains multiple e-mail accounts on the same service, it certainly beats logging in and out repeatedly! The additional benefit of reducing and/or negating online fingerprinting/profiling also adds to the usefulness of this add-on.

Highly recommend it, and hope its future is all but assured

RIP Tab Groups, until you get brought back from the dead :)