[throwawaysysd]

I detailed this in another comment, the reason desktops use it is to get those macOS-style permission dialogs that pop up when you try to take some privileged action. I don't think any desktop distribution wants to ask users to open a terminal and type "sudo usermod" and then log out and log back in in order to do something like setting the clock or formatting a usb drive. I don't remember this working well at all before polkit arrived either, I remember when device hotplug in Linux was really broken for this reason (and a few others). It's not reasonable to ask desktop users to edit udev rules when plugging in a new device. If it worked well at all it was because you were doing things like having a lot of suid/sgid tools or just running GUI programs as root which is a terrible idea.

>Who is trying to prevent the user from using their own hardware?

I don't understand this question. The functionality here is equivalent to sudo, you type your password to authenticate a certain action. As the sysadmin you can configure some actions to always accept or always deny, if you want.

[michaelmrose]

> As the sysadmin you can configure some actions to always accept or always deny, if you want

You can do this with sudo too.

[throwawaysysd]

Yes, polkit does have some overlap with sudo. What it has over sudo is a real API, programs can use it to authenticate an IPC request for an action to a privileged daemon while that daemon is running.