2. Bacteria isn't lurking between the bristles, because there aren't any.
Just like your toothbrush needs to be changed frequently, so do rotary cleansing brushes. The bacteria, dead skin, oil and debris has to go somewhere...yep, within the bristles. With an ultrasonic facial, you are deep cleaning and exfoliating your skin without bristles. Instead, simple wipe off the stainless steel blade with an antibacterial wipe and you are done -- Bye, Felicia (I mean, Bacteria)!