As a translator, they allow me to blow off some steam lol, whether I'm funny or not I don't care.
As a reader, I don't really care if they exist or not as long as they're at the end/kept to 1 page preferably, you can choose to skip em or read em you know? I just personally find it, idk, tacky? maybe when there's like, 3+ pages of "extras" in a chapter and that includes recruitment/credit pages (translation notes can get a pass if they're truly needed). I'm mostly a one man show so my credit pages are almost nonexistent but I personally try to combine any shitposting with my credits to not have a lot of junk in the chapter itself.
I also prefer an end card over lots of unnecessary notes for comedic commentary on the pages themselves as it distracts from the reading, though I am guilty of doing it myself from time to time and admittedly sometimes those kind of TL notes are hilarious. Just, keep it to a minimum lol