The confirmation is annoying for many GNU+Linux users. It's like asking are you sure you want to power off even though you had to use three or four keys or mouse clicks just to get to the poweroff menu.
It's not the total number of clicks that matters. It's the fact that several options (sleep, reboot, shut down) are the same final click and often a pixel or two away from each other.
That's why I use the terminal. On KDE it's even easier because I usually already have the terminal open in dolphin, so I just click into it and type "shut" and hit tab to complete shutdown. No accidental reboots for me!