The AI is the
primary instrument not the
only one hence the selective radial scan where you adjust the attitude and then scan the other instruments to see if it has the desired effect.
Just how do you recover from an unusual attitude in a helo without reference to the AI? Wings level has to be the first action to prevent further problems and you cross check with the standby AI to make sure the main hasn't toppled and got you into the UA/UP in the first place.
Sasless' trick of offsetting the pilots AI during the positioning for the UP/UA has been used for many years to the great amusement of many QHIs and IREs
