I wouldn't say it's worse than useless. But it may not be the panacea that we expect.
First, I have my doubts about the whole "A.I. Can Handle Anything" theory. Weather, accidents, and construction can create very creative roadways where you will want a driver behind the wheel who'll be able to figure out and work with human beings on the scene (for example, a cop doing traffic control around an accident).
So you'll still want drivers. The question is, how many drivers will you need?
Consider long-haul trucks, which are the ones that are really ripe for automation. They usually have two drivers so that they can run 24 hours at a stretch. I believe--and I may be off--that the rules for these people require that they drive no more than 12 hours. It might be 10 hours, I don't remember. But in any event, the reason you have two drivers is so that you don't have a truck spending 12-14 hours sitting by the side of the road while the single driver sleeps.
You could get rid of one driver right there. A long haul truck with one driver who can sleep for 12 hours and will only be woken up if something weird is going on that the truck can't handle so it pulled off to the side of the road. That's still saving money versus having two drivers and is certainly not "worse than useless."