Coltsfoot is only a weed, sometimes a slightly invasive weed, more often recognized by it's large green patches of leaves in the summer. When it blooms none of the leaves are visible.
But it's the first of a bunch of beautiful spring wildflowers that will be up in the coming weeks - Hepatica, Trilliums, Bloodroot, Leek and many others. Early May is the best single time of the year for a walk in the woods.