We're not talking about divulging specific attack plans. And, it IS useful to tell an adversary, "If you do this, fire and brimstone will rain down on you." Remember the promise to "make the sand glow red"? 
Trump has gotten a lot of mileage among his followers with the promise to not telegraph his moves. But this is not a free pass to use any military means without some congressional oversight. Only a dictator would want to be free of any constraints. Congress could engage a handful of those already tasked with knowing top secret information to review general plans.

I agree with your view. It just does not mean Trump has unlimited authority to do anything he wants without some oversight.