Is power-control working with rtcwake?

I am trying to get a utility script set-up as a daemon.
It uses rtcwake and some scripts to check if the laptop is on battery or plugged in, if on battery, it uses rtcwake to suspend until a set time.
with the power-control plug connected I was still getting permission denied errors for accessing /sys/power/state

I used the plug for system-files to access the /sys/power/state and the snap works as anticipated.
Have I misunderstood the purpose of power-control?
From the docs I understand that I cannot publish the snap to the store if I use system-files in this way.
How should I give rtcwake access to the power state stuff?