Does it make sense with "shits"? I mean really, if you stop to think about it, what does it mean to do things "for shits"? Is there a sensibly apparent meanin

Does it make sense with "shits"? I mean really, if you stop to think about it, what does it mean to do things "for shits"? Is there a sensibly apparent meaning, or is it like the word "cool", where people attach meaning that the word doesn't formally have? FYI, where I come from both phrases are considered reasonable. Without researching the matter, it isn't even clear to me that "shits and giggles" is the original phrase from which the other is derived. I suppose it's all a product of environment in the end. I share the general sentiment though. I heard all kinds of "interesting" phrases growing up that didn't seem to be pointful. For example, people who would say "P.O.'d" in lieu of "pissed off", and become offended if you used the actual phrase. I always felt it was silly. Use the phrase or don't.