Also opens the door to a lot of ultra-low-effort open source contributions that are done for the sake of it :/

I help maintaining a quite popular package ATM, I prefer when people do it for pragmatic reasons or for passion, rather than to improve their GitHub stats :/

But you can see them and filter out the low quality contributions. And ask about the good ones.

Filtering them out and dealing with the resulting drama is an additional drain on the maintainers' time.

Totally true, but I was talking more from a package maintainer PoV.