Plastic ID cards should eventually be phased out, but not yet. I believe that we do not possess any technology that can prevent a digital document from being modified. Maybe in the future a way of preventing counterfeits or modifications will be developed like what has been done with banknotes, and then it should be introduced.
At this time, plastic drivers licenses should not be replaced by digital in-app licenses. Online security in this country is not what it should be. This is just an open invitation to hackers to either find a way to get to people's personal information or figure out how to falsify and create bogus drivers licenses.
If physical drivers licenses were replaced by apps, the poorest people would be affected most. It would be just another aspect of our lives taken over by a technology corporation. It would create a necessity to have whatever technology that the app is on. Physical drivers licenses don't require more than a small amount of money and a large amount of time in a DMV office.
In the increasingly sophisticated mobile digital world, paper trails are starting to seem quaint at best and antiquated at worst, and the plastic, physical drivers license inevitably seems to conjure up memories of that world. On one hand, for the many people who already possess smart phones and regular mobile data service, going digital would be very convenient. Yet we cannot yet assume that everyone is in this position, and for those who are either too old to make the transition or who simply can't afford to, this move would be unfair.
The idea of having a digital drivers license should have people extremely upset. This would be a feast for ID thieves as they could steal a phone and have all your information. It also puts the burden of proof of a license on a machine. When we hand the laminated license to a police officer it should be one item that is unique to each driver. Not another item that can be hacked in a digital setting.