POSITIVE IMPACT. “However, the hypermutator subpopulation has increased evolvability because it has a much higher per-capita chance of producing the next highly beneficial mutation, or multiple beneficial mutations, than a non-mutator competitor (Fig. 3a). Thus, despite their slight fitness costs, hypermutators can sometimes hitchhike to fixation with the beneficial mutations that they generate.”
https://www.nature.com/articles/nrg3564