Andrew, that device would be poorly suited for the same reasons that I stated why a HANS device wouldn’t work for a karter. That Simpson product is essentially a HANS device but doesn’t require seat belts to secure it in place. It primarily protects against hyperflexion and subluxation, and nothing else, leaving a lot to be desired.
Greg, most people can easily touch their chin to their chest. If you can do that, you can very easily break a collar bone with the bottom of your helmet. Collar bones are fragile as bones go, it doesn’t take much, and you don’t have to have a neck injury to do so.