Here is what I have been told but Cuffs
In the old days the shirts came with one length of sleeves so if you had long arms the shirt would not cover the whole arm leaving it exposed to the elements, sun,cold and anything that would cut burn or scratch you arm. cuffs would protect your from these things. some used gloves with the gauntlets for the same thing. There where times when they would not need to wear gloves and so the cuff act as gauntlets on the gloves.
I have no idea if this is true or not but makes sense to me. as I have long arms and if I have a shirt that is short I can use the cuffs to protect my arms.
Mark