Self charging makes sense that the engine is pegged at most efficient rev to provide the necessary electrical supply.I'd say it's the other way around. Self charging is a con although I wouldn't quite call them that, the plug-in ones are not. And plug-in hybrids are also self-charging anyway (under braking or can switch mode to recharge the battery from the engine).
PHEVs however carries a big lump of battery and often times not very efficient yielding low 2miles/kwh. Often times owners don’t use plug in and just drive the car like a normal ICE and again PHEV vs equivalent ICE on ICE mode is way less efficient.
Self charging has smaller battery and is more efficient.