The always on talent cell backup seems to be working okay for me. I'd like to get something for my modem and router, that would last a while, but the power requirements are greater.
The thing is with an always on hub, you could get unintended results when power is restored. I had a garage door open on its own once because presence got confused because of no power to repeaters.
We had a power outage yesterday. We usually lose cable broadband along with power. It was interesting being still able to mess around with hubitat with backup power (generator) running.
Some GE/Jasco switches controlling outside lights came on as well. Maybe part of a greeting scene, but not sure. I have one GE/Jasco dimmer that comes on after power restoration as well, that's not part of any automation.
Weird things can happen.
I have a couple for phones, but they have a switchover period where no power is flowing, so you have to be careful on what you buy.