I find it a little hard to imagine that those devices outnumber things like stoves, dishwashers, washers/dryers, kettles, hair dryers... by 4:1.

Unsure why PoE would be better for LED lighting than the standard approach of screwing a bulb directly into AC, either. How many lumens do you get out of strip lights these days? And you still have AC-DC conversion for whatever's sourcing power onto the Ethernet link.