The advantage of long arms are that they make it easier to keep the offensive lineman from grabbing your body. I don't worry that much though. A defensive lineman who has good hand technique and actively use his arms will win the battles.
As for not participating in the bench press, I don't know why Sherrif didn't, but short arms are actually an advantage on the bench as the bar has a shorter way to travel from A to B.
I'm a fairly fit man, but I have long arms and I suck at the bench, barely able to lift 90 kg. Perhaps with focused training on improving the bench result I can get up to 110 kg or something, but it's definitely not my best exercise.