Introns get clipped out before protein synthesis starts. Mutations in non-coding regions usually do nothing to the phenotype of the individual. Within the coding regions of alleles, some types of mutations have no effect on the resulting proteins. Mutations do much more than cause genetic disorders or cancers. They do not occur only in humans.
Mutations are a way to introduce new alleles into a population.
This means, mutations increase the genetic variability of a population. Genetic variability is essential to the process of evolution and the formation of new species. Without mutations in the genetic material of some earlier primate species, we would not be here. Take me away.