flavor

[Funky Nasa]

Are there any benefits to flavor by chewing with your mouth open?

[Mahaloth]

I don't think so, unless you are experiencing so with other foods. Why would there be?

[Senegoid]

ISTM chewing with mouth open, or more to the point, breathing through mouth with food in mouth, enhances flavor. My guess: This brings the olfactory sense more into play.

[voltaire]

And a possible drawback to doing so would be to breathe in too hard and end up choking.