On a recent flight at T5 (CE) fast track security was empty, so we were through in seconds flat, however, I see no good reason if no one is using it that the staff are not utilised by processing other passengers, rather than paying security to stand around doing nothing.
Having said that, on boarding the person in front of me was ET , no status, and she was turned away politely by the gate agent, who then apologised to me !
I have been 'scooted through' fast track security at JFK when in WT, although when the TSA officer rather officiously said 'you, you and you, over here' I though we were in for 'special attention!'