The air to water thing is huge in the Netherlands too. I think it is because it’s the traditional way of heating the house. So people looking to replace it will want the same thing.
It’s even so that the word heat pump only is used for the air-water units, not the air-air ones, those are called airconditioners.
We changed to an electric boiler and air heat pumps, and have archived quite the reduction, certainly when the gas price went sky high.