I just saw them and wondered the same thing myself! I think they would work, not a bad idea actually but you would want them out quick if it started raining. My jacket is vented so doubt they would be of benefit....
I have a set- they definitely work to a point, but the problem is fitting them with your gear if you're an ATGATT guy and have sport-oriented jackets and gloves.
I wear full-gauntlet gloves and jackets that close tightly at the wrist- the Ventz units won't be exposed to airflow unless I tuck the gloves (along with the vents themselves) under the sleeves, which is pretty much impossible as the zippers/snaps won't close with that set-up (which is also a compromise in safety)- I gave up on the Ventz pretty quickly as they just won't work with my gear.
If you wear shorty gloves and a jacket with a relaxed fit at the sleeve openings, the venting units would be of some benefit- if you wear something like a Dainese or A* technical jacket, don't bother.