In automotive at least, it’s pretty common to size the evaporator and condenser coils based on their expected operating temperatures and (therefore) pressures. Usually this means condenser is a lot bigger than evaporator.
If you reverse the flow with the right valves and compressor setup, then the heat exchangers will still be sized wrong for efficiency. I suppose you could design a bidirectional system from the start that trades off for middling efficiency in both modes.
I’m not at all convinced that there are a substantial number of such bidirectional-sized residential systems installed in North America. But it’s also possible that the residential folks don’t care much about HX efficiency.
That makes sense, but also most heat pumps I know of are also AC units - like those mini splits installed in new apartments these days.
Would that not also be a balanced system?
And even if we’re talking about lower efficiency it’s still more efficient than burning gas in a furnace right?