You've listed three examples of products that changed the world, and have huge utility despite their danger. The main advertising for this product, however, seems to be that it allows you to tweet while you drive. So I don't think it's a very fair comparison.
I think the parent comment is referring to the lack of regulation of this product by regulatory bodies.
Cars are regulated to travel below a certain speed. Phones are regulated to their use outside of a vehicle (when operated by a human), and kitchen knives are illegal to carry in public.
While the parent comment is a little melodramatic, there's still something to be said regarding the safety of usage in this product and its affect on other people.
So we need to wait until some poor shmucks kill a few kids and pregnant mothers before we can realize this product (as currently advertised) is a bad idea? I thought we're smarter than that.
HUDs are not bad. But Navdy keeps marketing their product as a text-while-driving aid. Not very smart.
30k+ people die in car accidents every year in the US alone. These accidents are caused by a laundry list of things, including texting, eating, interactions with other passengers, fiddling with the radio, etc, etc. As cold and as heartless as this may sound, all sorts of products will kill people on the road, but some level is fatalities is "acceptable" when compared to the stifling and unrealistic alternative of aggressively policing every potential distraction.
Texting while driving is one of the most dangerous distractions primarily because of the interface: eyes off the road, hands off the wheel.
If Navdy can potentially reduce the danger of texting to a level comparable to that of, say, talking to passengers in your car, then I don't see how you can justifiably "realize" that it's a bad idea without seeing some statistics first.
