It is only when it can be made available to common understanding that it acquires utility within human society. But every effort should be made to make any peice of mathematical knowledge as widely known as feasible, and as accessible to as many people as is possible. By mathematical understanding , I do not merely mean knowledge of the relevant theorems and definitions. A monkey can be trained to recite a litany of theorems. This is not understanding.
Understanding is a subtle property, which exists in degrees, and has many facets.
Loosely speaking, a person's understanding of a particular mathematical result can be measured by how densely connected it is with the rest of their cognitive framework. The degree of understanding of a mathematical result is proportional to its potential utility to the understander . This fact goes unappreciated by those who seem to think that the real purpose of mathematics is the uncovery of unfathomable mysteries, or the careful construction, in the thin, cold air of high abstraction, of theoretical structures far beyond the human ken. Such a mentality can be called the Cult of Ramanujan. To such people, Ramanujan was a great mathematician.