What's the stance on edits where the only real change is deleting, "Thanks for the help in advance," or similar? I think it'd be best if the OP didn't write them in the first place but I typically mark them as 'no improvement whatsoever'. I think several users farm points in the Suggested Edits queue by removing these throwaway sentences, sometimes overlooking substantive errors or places for improvement in the post/title.
The general policy is that edits, especially suggested edits, should be somewhat complete. For "thanks" specifically here is an old post Is it Discouraged to Write 'Thanks' at the end of one's Post? that says not to edit only for removing that (there is likely still some room for doing it as a normal edit for 'active' posts, but that's a detail).
Thus, yes, if you come across suggested edits that just remove "thanks" and do nothing else, in particular on old posts and in numbers, you can reject them.
That said, I would not give too much weight to this farming points aspect. First, the points one can get that way is really not enormous and it is easy enough to get points in different ways. Thus, I don't see how it is a big issue even if it would happen. Second, framing it in this way just sours the debate. It's also possible somebody does that in good faith and thinks they do something good. Then not only do we tell them they wasted their time because we consider those improvements as too minor, in addition we tell them that we think they do so for bad reasons. That's a model case of adding insult to injury.