It is a cheat lol Showing Dead platforms is showing something your not supposed to see.
What I would like to see is maybe more sounds coming from sinking and broken up boats - that way we have a non-cheating way of confirming if something is dead or not.
Maybe add some debris in water for some effects.
But the sound of ships breaking up and flooding should be louder so we can pick it up on sonar and confirm the death of units instead of using cheats and mission status - that would be the most realistic.