Wherever a site involved American troops losing, I recommend that no property be retained for historical reasons beyond that needed for a sign on a pole.
It's a good thing that Americans won here.
Well, that's the thing about the Civil War......In every battle that was not a draw, some "Americans" won and some "Americans" lost.
As for the other point, do you really want to trade the Arizona Memorial for "a sign on a pole"?
Both sides were Americans