I have worn my gardener boots in dry snow and ice conditions after applying as much Obenauf's LP as they could absorb. The leather was not a problem, in that it did not get waterlogged, but there is no real ankle support or insulation from the cold. The ribbed rubber sole was Ok for grip as I recall. The elastic sides were not a problem until you encounter at close quarters an ankle deep pool of semi-frozen slush at the kerbside.
My official heavy rain and snow boot is my Tricker's Grasmere, again treated with HDLP. Bulletproof thick leather with a commando grip sole. Horses for courses.