USDA Zones vs EcoRegions
The conflict between the USDA zones vs Ecoregions is pretty obvious when you see them together. one is a broad approximation of climate across a continent and the other is a more nuanced map of the topology and regions of a state. Both are true, one is more accurate.
The USDA hardiness zones take into account the continental averages and impacts from the artic and the jet streams. The EcoRegion map takes into account smaller regional impacts of rivers and geology that is of a smaller scale. This is an important distinction.