I don't think the tool's a joke and or practically useless. I think there's quite a few things that it can help with certain mundane tasks, and by the way forget that it's in beta, it's also the first version of this project. The applications of GPT-3 in general (which I'm pretty positive GH CoPilot) can assist with all sorts of things, is the results perfect, far from it. However as of right now as a code completion tool it's just astonishing, that it does feel good enough to be like a junior programmer sitting and paired up with you.
Just how it predicts comments, and assists in documentation has been incredible. Outputting interfaces, or general programming tasks it's pretty spot on. General functions like sorting or other things like that you really don't need to think about. It understands your interfaces / protocols / etc.
I think the issue we should be discussing is with the in-question GPL code, how truly unique is it? Do we have an example of a line that CoPilot produced unmistakably coming from a particular project that is purely unique to that?