Need - Guess that would depend on the person and equipment.
For subs and speakers, their grrrreat. So many subs come with those little bitty feet, then want to upsell you for something better ( like svs isolation feet for $50 ) For your electronic equipment, good peace of mind.
But i can see why some may be hesitant to try them, after all the dont say audiophile, and aren't sold at an audio dealership. They are not over exorbitantly priced, so they must not be good for audio.
All im saying is for a couple of bucks, most are going to be pleasantly surprised. And if you don't end up using them on any gear, I'm sure there is something else around the house you can use them on.