Kishi is waiting for an epic moment to use it. Because it requires so much set up, it would be a bit ridiculous if Sasuke could use it constantly in fights; it requires that climactic moment of the battle when the thunderclouds gather over head for a final strike. Although I'm guessing that Sasuke's future power-ups will include some form of Natural Energy, as well as more chakra... so Sasuke might use it more consistently at that point, since he'll be able to harness/generate more lightning on his own.