

99% of the time I want to adjust the current lighting, I don’t want to first turn on all lights and then adjust all of those lights to a uniform standard before individually toggling them all individually. Powering on all unpowered lights when adjusting brightness should be the edge case, IMO (also again not just my opinion, but the industry standard)
For the record all other smart home systems treat room groups the way I am describing (like a dimmer knob and power switches). But there isn’t even an option in HA for rooms to “only adjust devices currently in use”. The smart home companies seem to have researched how people naturally intuit such things.

I know how it works, I’m just saying it’s unintuitive. It’s not how any other smart home system works.
I use adaptive brightness too, actually. But nearly every time I’m manually adjusting a room’s existing brightness, I don’t want every single unpowered devices to turn on, too.