FMC is not something that you learn. As the name says Fewest Moves Challenge, its objective is to solve the cube with the fewest moves, you can do it with any method you want and thats where the fun is, when you try to optimize your solutions you start learning more about the cube, you can do "weird" things you would not normally use for a speedsolve etc.
Of course, if you want to be competitive you should learn how to block build, orient edges and maybe methods like Domino Reduction.
But to answer your question, you shold definitely try FMC.