I think there is no definitive answer on this issue. A study by NIH shows NTM can form a biofilm in PVC pipes which is not dissipated by drying out. Another study of biofilm suggests it cannot be "rinsed away" by flushing pipes. There is research that suggests that copper pipe doesn't have the same problem. If NTM (MAC/MAI) is present in water it may aerosolize. Some suggest this as a possible vector of infection. But, if the NTM forms a biofilm in your pipes, no kind of shower head or cleaning of the head will eliminate it. To suggest otherwise is not supported by research. I would be cautious about succumbing to a sales pitch, thinking it was somehow keeping me safe. I minimize time in the shower and we set the water heater to 140F to inhibit growth.