If it doesn't seal out the elements then there is not much value there.
Crash protection would be the next question. The older I get the more paranoid I get. I have 4 kids snowboarding so I have a lot to be paranoid about. Do you think the chin guard would withstand an impact with a rail or tree?.
The better design would be a goggle and chin guard that pivoted up when necessary. If it worked like this motorcycle helmet that would be a big improvement. The goggle fog issue would not be solved though:
The mouth piece is ok for small branch impacts/scrapes, I would not count on it in a serious collision like a proper ski racing guard.
“I train every day of my life as they have never trained a day in theirs.” – Alexander Karelin