Yeah - two themes here -
1) Is copy even important?
I think it is. If this post was titled, "Auto-tune experimentation for short-form content optimization", it might make half the audience confused about the product. In fact, the 1-liner we use for HN is very different from when we talk to VCs, because the audience is different with different goals & backgrounds. I guess the point I am making is that messaging has to be contextualized, depending on users, platform, and goals.
2) PMF vs copy - I agree that the two are orthogonal. Copy is not going to solve for the lack of a PMF (and it shouldn't). Exactly the point above - the goal is to help more and more users comprehend what you do, hopefully in a way that's more personalized to them.