These are marketed to give your kickstand a tip that won't sink into the dirt as easily, but they also protect the surfaces you park them on. With these feet on my bikes kickstands I can park them inside without worrying about damaging my hardwood floors. They also help when parking on an incline - because the rubber foot won't slide across cement like the bare aluminum kickstand will.
These are on my duel Pletscher kickstand on our tandem bike, they do add balance to the bike when on the stand for dirt conditions, but for some reason my kickstand wore though the rubber grommets in about 3 months. I still like the product, but if you cut off your kick stand make sure you round the edges of your cut.