That, plus the existence of chipsets used in those switches, such as Realtek RTL8372/RTL8373 and RTL9303. Feature rich yet dirt cheap.

I particularly like per-pert PoE power monitoring on the RTL837x. I hooked that up to my netdata to get a full history of how much each device in my rack is drawing. Don't need a fancy PDU or separate power bricks for each device -- everything is powered by the $60 switch.

(This is a home network and I'm not at all bothered about single points of failure or lack of redundancy/failover.)