The only thing I know for sure about comp picks is that they cannot be traded.
What they do is gives a GM an option of trading.
Lets say The Packers do get 2 6th RND picks.
Ted has is eye on a guy who is not going to drop to the bottom of the 5th RND.
He could bundle his 5th, 6th, and 7th picks to move up in the 5th to grab the guy knowing he still had his 2 comp picks to use at the end of The 6th RND.
That flexibility is one advantage I can see.
I was addicted to The Hokey Pokey, but I turned myself around!