Reacting to your first point: As far as I know (western europe), heatpumps mostly are used to heat water to then heat your house, and renovating generally means reducing breathability of the house itself, which, combined with the temp difference, means condensation/mold problems. You then have to correct that by opening windows intelligently or installing air ventilation, and then a heat exchanger to not lose too much heat. Like you say, it seems to be a no-brainer then to instead combine heat pump _and_ ventilation, so that the ventilation itself works with a heat pump.

The only counter-argument I have is that if all the heating were done using ventilation, you might have to live in a very windy house, but I feel like entirely decoupling the two is not the best solution to that problem…