Wireless technology of anything offers convenience in the expense of reliability. Here are the expenses:
1) AC powered wireless device still needs power cabling and that defeats the entire convenience advantage.
2) Battery powered device, especially in outdoor environment, is less reliable and poses a much higher maintenance pressure, which is much more than simply replacing dying batteries.
3) Wireless devices also pose unnecessary logical security risks by exposing security network to the untrusted.
4) Wireless devices require additional backend system support and thus adds to the overall cost and future maintenance pressure.
Our principle, in our mission critical security function, in applying wireless technology is that we do not do it unless there is absolutely no other way to achieve the same intended outcome.