Cristall, imho, is the typical player that put great numbers in junior, but has a playing style combined with his frame/(lack of) strength/skating that doesn't translate well to the NHL.
Too much fancy plays that wouldn't make it in the NHL.
He's smart, he has a great hockey sense, but he likes it cute. It's efficient in the WHL but in the NHL, the passing lanes he's exploiting on a constant basis won't be available.
Plus he's small, not that strong and his skating is ok, which is not ok for his size.
In comparison, Benson has a style that is more pro translatable. He's not that fast but is more direct in his approach. His skating agility is better. Do not rely as much on cuteness/fanciness.
IMHO, Cristall will make it to the NHL because he's smart. But he'll be more of a complimentary player. A PP specialist, a typical offensive exploitation specialist.
I don't think he's gonna become an impact player.