RDL is one of the difficult exercises to teach people, because not many people can contract thier hamstrings when they're doing RDL or back extension exercise.
Remember that the weight doesn't help you to contract your muscles like DB doesn't help you to contract your biceps. You must contract your muscle by yourself. By the way, contraction and tightness are totally different things.
RDL can strengthen your posterior chain to improve your gym performance and sports performance like cycling, football, rugby, rowing, basketball, running...etc.