(analogy: learn to fuc.king fly right)
But how do you know if you are flying right? In training I see many pilots whose performance can at best be described as marginal, yet they think they are doing a good job because certain training providers will tell them that regardless of how poor they are.
Used properly FDM is a tool for you to assess yourself - in most companies you can ask to see the data on your own flights. And it doesn't matter how good you are there is always room for improvement.