1. You don't need to pay anyone to get better at cubing, J-perm / TheCubicle / CubeHead have good tutorials
2. My friend who bought his course said claims he didn't get any better
3. It's not about the content of the course it's more about the work ethic , if you can devote the time to do a lot of solves and such then maybe you can buy the course as a supplement but you shuld practice a lot to make it work