I think we have to know the order in which these features occurred. As others pointed out, chewing has other benefits. Maybe evolution took advantage of chewing to change the air intake design for some other advantage.
I thought of this, as it could also be the other way around. As in, hey this food is already chewed because of the air intake design, resources can be allocated elsewhere instead of spending them on digesting. Or it developed completely differently I'm actually curious as to what the guesstimated order is.
