I think that the diference between pg and PCG depends not much on the algorithm that designs the content but more on how the content is used once it is generated. For example you could take a conventional game and generate the textures on the fly to reduce filesize or whatever. That would be pg. Or you could generate that same texture, and from that texture shape the map, or use it to allocate resources, or do something that affects gameplay. That would be PCG.
Just my interpretation.