[Mvandenbergh]

In many places (but not the US because of thermostat standards) HVAC systems are now typically inverter driven as well so that does remove some of the advantages of three-phase since any individual load is single-phase anyway.

[briHass]

Many HVAC systems in the US also use inverter compressors now. The efficient units (which includes most minisplits) are inverter. The efficiency requirements of the recent government subsidy program pretty much requires an inverter.