Had Finn and Rey learned the force so fast because the film must prove that women and afro descendants are better than everyone.
Just lost of skin finish would not result and so robust metal structure in Luke's hand. If you put skin over such thing if would be much larger than a normal hand.
If he don't care about scar, why did he made a tatoo over it?
At least the Galatic Empire is like me, they prefer CRT over LCD :
