Why do most buckskin jackets and coats have fringe?
Fringe (also used on shirts and pants) prevented rain from soaking the body at the seams by draining the water off the garment. It was also used for string; if you needed
to tie something, you just cut off a piece
Secondarily, it was used for decoration. A mountain man re-enactor told me fringe projected a menacing appearance when one was under attack—much the same way as when an eagle ruffles its feathers.