This is from what I have observed in singleplayer games.
If you click on an enemy tactic then you can compare if their tactic is better with their composition and use a corresponding counter-tactic to gain an upper hand.
You are in effectively simulating what would happen if the enemy picked THIS particular tactic and can plan around it.
IE If you see close vs close and you will have high loses. So you change to another tactic that has less chance of a bad match up.
There should be a % compatibility number below each side's tactic box try to aim for highest average. IE if all of your ship have nothing but close-range weapon you might want to pick close. Eventually start mixing it up if AI is getting better compatibility than you are.