Good luck finding reasonably priced switches and low power PD ICs that support type 3 or type 4 PoE. Also, supporting those tiny pulses requires large capacito

Good luck finding reasonably priced switches and low power PD ICs that support type 3 or type 4 PoE. Also, supporting those tiny pulses requires large capacitors to hold a charge in between pulses. That plus the required magnetics make PoE sensors way more bulky and expensive to manufacture than old fashioned RS-485 sensors.