A heads-up display is safer than having to glance down, taking one’s eyes off of the road in order to check one’s speed, or other operating parameters. As long as people aren’t hacking it to watch porn or Game of Thrones while they drive.
I really never saw that as a problem-but that is just me. And I would not put it past some people to do just that-they are already a hazard texting and jabbering on the phone-it makes my hair stand on end every time I see someone multitasking on the road. I think it is safer when people are more involved in driving, not less.