racing fuel with oxygen sensors

Was at the tuner's Monday getting a tune and dyno and he suggested adding 116 racing fuel in the tank. Said about 5 gallons in a 16 gallon tank. I still run both the front and rear oxygen sensors. Won't this hurt them? We don't drive on the street anymore; only race. His thinking was that it helps with possible detonation on launch ... which I've never heard of either. Worth it or a waste of money? It's a stock LS1 and we run 93 gas typically.