I don't believe that this is correct. Yes, you need the valve. But at each end you need a device capable of either radiating heat to the atmosphere or absorbin

I don't believe that this is correct. Yes, you need the valve. But at each end you need a device capable of either radiating heat to the atmosphere or absorbing heat from the atmosphere. Although the principles behind both processes are similar, heat pumps & minisplits (the indoor part of the system) are fairly distinct from each other. Others have already mentioned the much greater volume of air that a heat pump typically provides service too, additionally.