Safety is always the first concern and this is true for motorcycle riders. Proper operation and maintenance of the motorcycle is important, but so is their physical safety while riding. Leather chaps are recommended for motorcyclists because they increase the rider's leg safety level.
The main function of leather chaps has always been to provide protection to the legs, which is something all riders need. Chaps can help offer protection from flying debris while riding, but also from the cold feel of the wind.