Mh, I have an academic background in electrical engineering with focus on energy storage (primary), power electronics (and grids). I must say, in terms of academic knowledge the distinction made in that explanation is nonsense. MPPT devices also use pulse width modulation as an underlying technique but have another layer of feedback control on top. I also don't think that you can say that the power electronic circuits are generally different between the two. But of course that additional control layer probably means there's additional microelectronic circuitry.
HOWEVER, I know marketing people and maybe the distinction presented there makes sense when talking about actual products on the market and under which product categories they're sold...