>much more value from validating and improving your equipment and its handling than the actual "cost" of revealing its capabilities to adversaries in almost every conflict.

The value of carrying a big stick is lost when others see the stick breaks after a few swings. There's value in maintaining military kayfabe - revealing hand in sideshows and losing deterrence for main events as result can be much costlier down the line. What was learned that wasn't already known and deliberately avoided in polite conversation?