[dashundchen]

I live in the Great Lakes with a heat pump heating in a drafty Victorian house. The heat pump came with resistive heat strips but they only kick on a few days a year.

Once I airseal some more and fix some of the leaky storms I expect it to never resort to resistive at all.

Heat pumps do work in cold climates.

[Tiktaalik]

and imagine it wasn't a drafty victorian, but rather a new build passive house with incredibly good insulation. One would probably be fine with the heat pump alone.