Though these edits are sometimes rejected for being too minor.
If you wanna make the most of editing on Stack Exchange, you should read In Defense of Editing:
If you are going to edit a post, make sure you’re substantively improving it. Avoid making isolated, trivial edits, as they are the source of much friction. For example, don’t bother changing “its” to “it’s” unless you have several other edits to make in the same post. There has to be a legitimate case that your edit made multiple changes transforming the post from good to great — or at least substantively improving it.
To be very specific, I would discourage editing a post solely to remove salutations like “hi” and “thanks”. That’s just adding an unnecessary edit on top of an unnecessary set of salutations. I completely agree that salutations add little to a question or answer, but if you’re going to take the time to go in and remove salutations, fix the whole post while you’re at it! If there’s nothing else to edit, then don’t bother.
These guidelines are good ones to follow whenever you're editing, regardless of whether you need someone to approve the results or not. If you're stepping in to improve the post, do everything in your power to accomplish that goal - don't make one little change and then call it a day.
Do we discourage signatures? Sure. Is the presence of a sig reason enough to edit an otherwise perfectly-good post? Probably not. Make your edits count for something.