Auto battle mode

So I never really understood this mechanic but when I need to actually do something, I decided to give it a shot and see what it does before I walked off and do something else. It seems that if any of you have never used auto battle, it's just the game goes through with the AI controlling your units like normally.

So I thought what if this is a good way to actually test out a defense team that you made in the training tower, since you normally can't watch an AI doing the arena defense so you'd have to hope they did something good. Maybe if you construct a team and go to like maybe the 10th floor of the training tower, you can test out and see how your team fairs. Maybe you guys might find this pointless since you always observed the AI from the opposing team anyway and have an idea how they function, or you guys already knew about this but maybe it's worth something to note?