Plus when you start shooting at the target at angles other than straight broadside..quartering etc.. You can visually see where the path of the arrow will take it to the exit.
And this is a GREAT time to teach this to young hunters. You can do so with an arrow while they're in their tree. I did this with my son last year.....and it helped him visualize the path his arrow needed to take.
GREAT point. You can't do this with a bag or block.