It's all in aid of some streetsweeper being able to add "contributor to X, Y, Z projects!" to their GitHub résumé. Before LLMs were a thing I also received worthless spelling-incorrection pull requests with the same aim.
I think a true spelling correction would be welcome. But I think the kind BS attitude the GP is describing often leads to useless reformatting/language tweaks, because the goal isn't to make the repo better, it's to make a change for making a change's sake with as little effort as possible.
I always find it a pity when someone has been clever and it's missed. "Spelling incorrection", get it? It's not a correction. It's the opposite.
On the flip side, I used to get a lot of spam PRs that made an arbitrary or net neutral change to our readme, presumably just to get "contributor" credit. That is not welcome or helpful to anyone.