As long as it's only a little below freezing. Try that in Norway, or even somewhere like Austria, and see how it goes.

They work just fine until -25C or so. (COP around 3). After they they still do work you just fine but work effectively as resistive heaters as you approach COP of 1.

Obviously you need a model they is made for which winters but people use them all over Finland including Lapland without any issues. If you want to save some money on the coldest days you burn some wood in the oven/fireplace if you have one.

edit: heat pumps (both air and ground) have been very popular in the nordics for quite some time now. One big reason is that we have cheap electricity and very expensive oil/gas. Lately also municipal level central heating networks have been slowly moving to heat pumps as their source of heat.

Then you'd just use "old fashioned" electric heating