I have tons of tabs open but tab grouping is an anti-feature. It takes way more time fucking around with tab groups, opening them, closing them, moving then around than I've ever saved by using them.
Yeah, I've had close to a thousand tabs open regularly on my main system, but I just use windows as my tab groups (and workspaces as my window groups). Another layer of grouping isn't what I need to manage that better.
I do think it's nice to have as an option for the many people who seem to want it, though.