Aluminum Keys... why??

[JD401]

Hi all, this is my first real post!

I've been wondering what the purpose of aluminum keys were/are. I have a key ring full of old YALE keys, various logo styles, all aluminum. Obviously, they won't rust, but neither will brass. They are light, yes, but aren't they also brittle? I assume they will crack instead of bend.

Can anyone shed light on the purpose of aluminum keys?

Below is a photo of a small selection...

JD