Not sure where that misconception came from.

The issue here in New England is that not much of the existing residential housing stock is ducted heat (or ducted A/C), so it's either splits or a huuuge amount of interior work. Recently there are some air source HPs that can make the 'hot' end hot enough that it'll work with a hydronic (hot water / baseboard) system — so we might be approaching the point where a HP just as a furnace replacement is one of the options.

And that’s without getting into air vs ground. Not just efficiency, but how likely the refrigerant is to be released to the atmosphere (just think about all that hosing going to / from splits).