I'm guessing your telemetry will tell you a lot of users have started using tab groups. They may have done so by mistake. My tabs each take up like half an inch of the screen and I don't have a gaming mouse; I now have multiple tab groups which I never intended making. As this is a quite technical feature, maybe dragging should be off by default, or only when e.g. holding shift and dragging or something?

(Yes it's a beautiful feature and probably lots of people want it, just noting that the dragging is confusing. I can't think of a good way to solve the problem that doesn't make it slightly more difficult/nerdy to use.)