I'm sitting staring at an 8W filament led Edison bulb, 800 lumens. For a zigbee bulb I found, 11W, 1100 lumens. And I think they include ZigBee overhead in their 11W? Don't even need PoE+ for that.

It would just come down to chip and maybe power cost difference between Ethernet with PoE vs wireless with traditional 120V electrical wiring. Pretty pointless to retrofit I'd think, but for new construction it could be viable.