This was the biggest question I had about last year with their use of Parker. You love to have a receiver who can consistently win 50-50 balls, but why in the hell would you design an offense where plays are passes are supposed to be in tight coverage and the receiver winning 50-50 balls. That was literally the plan. Mac Jones talked about several times. It just seems dumb that you design plays to throw to the covered guy and hope he wins the battle for the ball. When a QB throws a 50-50 ball, it is typically to a receiver that was supposed to get open, but didn't and the QB just trusts him to get the ball and tries to throw it to the best spot possible for him to win the ball.
Parker is a great 50-50 ball catcher, but they shouldn't be designing play after play for him to catch 50-50 balls.