I wouldn't normalized power is better, it is used for a different purpose. Average power is the real work that you did, Normalized power is an estimation of the metabolic stress on your body. It is calculated with a rolling 30 second average of power^4. This magnifies (rewards) spikes in power and lessens dips in power. Very steady state power output will have NP=AP and very "spikey" power will have NP much higher than AP.