In the 2010 comic book mini-series "Batman Beyond", Dick Grayson explains that there is also a tactical reason for adding a cape to the costume: misdirection. It "hides the body, makes it difficult to know where to strike" when Batman moves, with the result that villains attacking him at long range cannot determine whether they are shooting at Batman's body or just the cape. A flashback reveals that after armor-piercing rounds from the Joker's gun penetrated the cape, it saved Bruce but Dick, who was behind him, was critically wounded. It explains why Bruce eliminates the cape on the "Batman Beyond" incarnation of the Batsuit, as he'd rather be the one who got shot instead of others.