I like this approach. This kind of house-wide reaction to putting my phone on a wireless charger would make me more trusting of the damn things. I only used one briefly, twice in a month where my phone didn't charge, then died, and having no alarm to wake me in the morning all because my phone wasn't perfectly positioned on the pad soured me on the idea.
I combine those and a few other things into a hybrid Boolean sensor called “sleep conditions”
At any point in time the “sleep conditions” sensor is calculated as “true” or “false” - ie. does it look like I’m likely to be going to sleep.
So when my phone is placed on charge AND sleep conditions = true, my automation goes into sleep mode triggering lights off, setting wake up alarm etc
It seems trivial, but simply putting your phone on a wireless charger at night and having everything react automatically is quite gratifying!