i used to back alot of bows,,, just because I liked the way it looked,, very nice to put art work on etc,, and It can add protection for harsh use,, I agree optional most the time,, but sometimes if the back is compromised,, it could make a difference in the success of a bow,, Pope and Young liked to back their bows and stated they had a higher success rate when they did so,, their bows were heavy,, and the rawhide may have had a positive effect on wood that was under more strain,,or a lesser quality wood??? if you have alot of experience easy to tell if needed or not,,but if in doubt,, it will not hurt to back one,, and it is beautiful,,