not guarantee does not mean useless, just as money does not guarantee happiness, does not mean money is useless
We often hear that: Fools are defeated by smart people Smart people are defeated by courage People dare to be defeated by desperate people People desperate to be defeated by a madman And all those people are defeated by the lucky ones The lucky ones look smarter, but in fact they train special thinking: how to recognize (intuition) and consistent (logical) do ingenious things (not cunning).