First, why using PoE ? Real wireless doesn't exist, you will need at least one cable for power supply. I don't know of any professional solution that works on battery only. Then whatever some people may say, I don't feel wireless data transmission is really secure. So why not combine data and power supply in one cable. Furthermore by plugging your PoE switch on an UPS you prevent a thief disabling your surveillance system by just turning off the house main breaker.

Have you already installed such system ? The cabling has already been installed, I'm now looking for pan/tilt indoor cameras that are not too ugly and bulky, if you could recommend reliable brand/model, I would really appreciate it.

I agree about Wi-Fi secrity, and also it must be considered that Wi-Fi could be jammed which a wired signal cannot be.

PoE saves exctra cabling and power supplies, however it is unusual to see PTZ cameras that are PoE due to the power demands of the motors. Although they may exist I am not awae of any and certainl have never seen them in a professional installatoin.

Consider multiple POE cameras instead of one PTZ camera. Many times it is best to have at least 2 cameras, each covering the other camera. If there is only 1 camera, it maybe approached from the non-viewed area, and disabled. The variable focus cameras are quite nice.