It does heat the east coast of the U.S, but not nearly as much as Northern Europe.
The main complication is that prevailing weather tends to move west-to-east (because of the Coriolis force at typical U.S. latitudes), which means the east coast gets more continental air masses from Canada and the Plains than oceanic air masses. But compare Boston to Chicago, NYC to Kansas, or Washington D.C. to Colorado. All of the former are at higher latitudes, but tend to have milder temperatures than the latter. (Some of this is due to the moderating effect of water in general, but winters in coastal Boston are generally milder than in Chicago despite the latter also being on water and at a lower latitude.)
The main complication is that prevailing weather tends to move west-to-east (because of the Coriolis force at typical U.S. latitudes), which means the east coast gets more continental air masses from Canada and the Plains than oceanic air masses. But compare Boston to Chicago, NYC to Kansas, or Washington D.C. to Colorado. All of the former are at higher latitudes, but tend to have milder temperatures than the latter. (Some of this is due to the moderating effect of water in general, but winters in coastal Boston are generally milder than in Chicago despite the latter also being on water and at a lower latitude.)