If I recall correctly it prevents the Gazelle for making too wide of a bank and other small things. It's designed to keep you safe while you learned to fly. I stopped using it after about a week,
I find that with both rolls and loops having a lot of altitude is good. You need it to recover. With both I find that being at about 150 works best speed wise for me. If you really want to test your luck, try an inside loop.