actually not always. Reset triggers a board reset (a soft reset, if you like) Powering off and on (waiting 20 secs before power on) performs what is more often known as a cold boot, especially if you pull the power lead before power back on.
I use the reset button often, why wait 5 seconds holding the power button when I can have the computer restart instantly? I'd spend hours holding the power button down when overclocking the computer or installing new hardware if I didn't have a reset button...
Reset button is also handy if (ahem) your girlfriend/wife bursts into the room while you are watching something you shouldn't...![]()
But then your left there with your hand down your pants staring at a blank screen! That's not normal!![]()