Hooking it up to other Government systems such as tax, health, immigration, etc could be pretty useful. Currently each of the departments have to figure this out itself, and it is pretty messy from my understanding.

With an ID card, I probably shouldn't need a drivers license or a passport ( ignoring that some contries still stamp your passport, so this might not be achievable ). But I also probably shouldn't be required to carry on unless I'm trying to do something that requires one.

Once we've paid to solve the issue once, we shouldn't be paying over and over again. Next, once you have an identity, do you really want your bank or equifax to pay and build for the exact same thing? Sure they're private entities, but they're private entities that you can't avoid who pass the cost back to you, so why pay again?

On the other hand, this would likely make things like the porn pass easier to implement, so maybe we need to sort out the fact we're living in a nanny state first.