It depends on the manufacturer. I worked at Mazda. They have one that projects the next turn you need to take, the speed limit on the road, and the speed of the vehicle. That, is actually a very nice system, because your eyes are never off the road.
I've also seen older Mazda ones that had only the current vehicle's speed... That, I find pretty useless.
So it could be a total gimmick, or a great add-on, depends on how it's implemented. My guess is that it will be a pretty "smart" HUD, because it's an EV, and people expect high-tech to be top of the line.