Because he exclusively runs against light boxes. Teams have to respect Allen or he will burn them.
Another thing YPC doesn’t account for is obvious running downs. How good were we last year at getting 3rd/4th and short? Pretty sure I saw a stat that we were bottom of the league.
He’s worth even more than a first, considering the Bills will have a very late first.
Biggest issue would be cap. But like someone else said, Raiders are still very much in the playoff hunt. No way he goes anywhere.