That's a core problem with this. If people with expertise can't even tell us clear boundaries of its truth, how is anyone else going to come to rely on this for that purpose. I mean, you could say you defined a fuzzy boundary and I shouldn't trend towards that boundary from the wrong direction (re: text games that use different tokens than the ones it was trained on) but, how will I know if I'm too close to this boundary when I'm trending from a direction of doing things it's supposed to be good at?
It can't play tic tac toe, fine. But I know it gets concepts wrong on things I'm good at. I've seen it generate a lot of sentences that are correct on their own, but when you combine them to form a bigger picture, it paints something fundamentally different than what's going on.
Moreover, I've had terrible results with it as something to generate creative writing; to the extent that it's on par with a lazy secondary school student that only knows a rudimentary outline of what they're writing about. For example, I asked it to generate a debate between Chomsky and Trump and it gives me a basic debate format around a vague outline of their beliefs where they argue respectfully and blandly (both of which Trump is not known for).
It's entirely possible I haven't exercised it enough and that it requires more than the hours I put into it or it just doesn't work for anything I find interesting.