In The Oregon Trail on Apple II / Mac, what is clothing for?
Clothes are only useful for bartering with traders or Indians. I did not have the opportunity to play the original on the Apple II, but I found an online version that is exactly like DOS version. The graphics may be different compared to the Apple II. You can play it here: https://archive.org/details/msdos_Oregon_Trail_The_1990
I played through this many times for fun, and I have found no other purpose for clothes than the ones you stated.