I understand acne scars can't be completely cured but can microdermabrasion actually help make them less visible?

Yes: Absolutely - depends upon how deep they are. The older treatment was microdermabrasion which was effective because it went deeper. The medical community has figured out that a series of microdermabrasion is equivalent to one deep dermabrasion. Remember it can take 10 or more treatments to see some improvement. When in doubt consult your dermatologist or plastic surgeon.