Actually helps the soil texture too, not just feeding them. Those grounds make heavy dirt clump less. Lets water get through better so the roots aren't sitting wet. Also seems to keep some bugs away, noticed fewer slugs. Pretty cool it fixes more than one problem. Makes the whole garden smell like a cafe after it rains.
Wait, is it REALLY that big of a deal? Like @annanguyen said, seems like a small thing that could mess up the soil later. My plants are fine without it.