It's really unrelated - it's more about the hash domain being rather small, i.e. 52. I would think that if you substitute the counting (go to card N+value) to p

It's really unrelated - it's more about the hash domain being rather small, i.e. 52. I would think that if you substitute the counting (go to card N+value) to proper hashing (go to card md5(value)%52) you would get the same, if not stronger, result.