Add permissions mention to man page
Would love to see the very useful considerations on permissions relayed in the man page as permissions issues could be confusing at first on such a utility.
Love the project btw
IMHO: systemd-enabled distributions should build brightnessctl with logind support, meaning that when the user is physically logged into his machine he should not have permission issue witch should cover most use cases.
I know that at least ubuntu doesn't ship logind support (see https://bugs.launchpad.net/ubuntu/+source/brightnessctl/+bug/2076317 ) but archlinux and fedora do
It's really the distro's job to make it properly work, if it ships broken brightnessctl or doesn't document that you should add yourself to certain groups, you should nag your maintainers. logind way is slow af so it's really a fallback for systemd-based distros that don't bother to make it work properly.