Especially the deep ball. That's what makes Milton so effective. He's an ok runner, but nothing special. Not big enough to bull people, not fast enough to outrun defenders, and not quick enough to elude. His runs, however, are very effective because he's doing it against a numerical advantage and that comes partly from having to respect his deep ball.
That's this offense, putting a defense into numerical disadvantages. With an accurate passer that can run even a little, it's very difficult to stop. Milton has a very good completion rate for how often they throw deep balls.
2nd in yards per attempt, 2nd in completion percentage, 2nd in QB Rating. All to Baker Mayfield.
That's elite. The vast improvement he made from year 1 to year 2 has to have any potential QB salivating.