Why do people play CP Adagio?

He does absolutely no damage against an Aegis, like close to none. Even with AC BM FB you don't even scratch your enemy. Doesn't matter if you have fire on them and use your B, you don't even scratch your opponents. I would love to hear the opinions of adagio mains, Adagio is the one hero that i have never won with, even if im not the one playing him.