Nitro isn't necessary when running in an engine especially for a ringed engine that needs quite a bit of bench running because it's a waste of money. An ABC type runs in much quicker (well enough to go flying anyway) so you might as well use whatever fuel you're going to fly with. The one thing you have to remember with nitro is that if you change the % used then you must retune because the higher the % the more the needle must be opened. This means shorter flights on the same tank. It's not because the nitro burns hotter, it's because of the air/fuel ratio it needs to burn properly because it's way different to what methanol by itself needs.

Nitro isn't used much outside of America purely because of cost. I've never used it because it doesn't give me any benefit.