I am never handing my phone to a cop.
replies(3):
The point is that you don't have to:
> To present a Digital ID in person, users can double-click the side button or Home button to access Apple Wallet and select Digital ID. From there, they can hold their iPhone or Apple Watch near an identity reader, review the specific information being requested, and use Face ID or Touch ID to authenticate.
"hold … near … review"
If you're (e.g.) buying alcohol, then the "specific information" would be your birthday, and that is all that would be sent over. With a regular ID, verifying your age would mean handing over your physical card which would have all sorts of other non-relevant information to the task at hand.
Further:
> Only the information needed for a transaction is presented, and the user has the opportunity to review and authorize the information being requested with Face ID or Touch ID before it is shared. Users do not need to unlock, show, or hand over their device to present their ID.
AIUI, cops would have a verifying device or app and the information requested—which you authorize—is sent over wirelessly. Kind of like how you no longer have to hand over your credit/debit cards to (possibly malicious) cashiers, and just keep it in your hand and tap. (Older people may remember the carbon copy 'ka-chunk' machines.)
With a physical ID you have to hand that over because that is the only way the information can be read off of it. With a digital ID you can send a copy of your ID without physical exchange / handover.