I use clippers to shorten my pits and bush because my pit hair pulls in weird ways and my bush will mat with blood clots and it helps trap less smells in both but other than that yeah there’s no reason. I once had an A&P professor who went on a mini rant one class about how "the leg and arm hairs are for detecting the movement of fleas ticks and other parasites and how could women be asked to give up such protection? "