If it's just a single PoE, why not long Ethernet cable from wherever the main Internet connection is? Because you still need the PoE cable, so why not send data over it?
Ubiquity is fun but expensive and in addition to the transmitter you also need a computer (read: RaspberryPi) to run controller on. Mesh generally make only sense when you have a number of these, repeating signal between them, not just a single one.