diffuser vs air drying

shakeshake Posts: 404Registered Users
i've been contemplating getting a blow dryer and diffuser attactchement for a while now but am a bit stuck.

for those of you that use a diffuser, what is the main difference/benifit of using a diffuser vs just letting hair air dry? does it allow for less poof? more definition. please help before i spend any hard earned cash. lol. thanx ladies...