The advantage relates to the acceleration time and displacement of the pulsating flow common to the mechanical pump. High compression ratios can be used with nitrous but shifting the maximum pressure after top dead center becomes more and more difficult. I prefer to use street compression ratios and then just work with adding more nitrous to get desired horsepower levels. We are currently testing some pistons specifically designed for Nitrous use. Most of our effort has been to develop new ideas that will push the limit of nitrous technology.
More testing is planned with a piston especially plated to reduce detonation.
A beginner would do well to build a reliable high performance engine first, then advance to nitrous, turbo or supercharging. This makes for more fun, more education with less head ache and money spent.