Stylistic Differences of High Blocks

My sensei always tell me to high block, age-uke, with the ulna facing outwards. This makes sense to me because your arm is stronger in this position, and a bladed weapon would have more trouble cutting you.



My confusion is because I keep seeing photos of karatekas online who block with the palm facing outwards, and the fleshy part of your arm exposed. I understand different styles have different methods but I'm curious what benefits this would provide. Does anyone know?