IIUC grandparent is in Norway as he quoted the price in NOK.

Oh good catch. Somehow my eyes skipped over NOK and just saw the $2.3k.

... Why does someone in Norway need a split AC unit? I don't think they're very efficient for heating.

EDIT: I researched this and it seems the type designed for heating in negative zero temperatures are much more expensive. So maybe that explains it?

Similar to Finland. Quite lot of time in the year like right now outside temperature is above zero, but below say 15C. So heatpumps are in very good efficiency range.