the usual method of drying brushes in a cup placing them bristle side up is bad for the brush. It causes the water to seep down into the glue holding the bristles and causes it to deteriorate and lose adhesion. which can cause unwanted brush hairs in paint jobs as well as the bristles fraying from the bundle.
The brush drying rack solves this issue by orienting the brushes to dry upside down and guide the water away from the glue to prolong the life of the brush. as well as allowing the bristles to be hand shaped into their original from while wet and to dry and stay in that form.