Here's the thing about 'just show them your license and go on with your life'...
When Officer Friendly conducts a field interview and interrogates a subject (even if the subject isn't actually suspected of a crime At This Time, he's going to write down what he's found because no one can really be expected to remember every tiny detail for weeks and weeks. Since we no longer use quill pens and parchment it's quite likely that this "writing" will be in a portable computer which will remember every teeny detail for months and years.
Since Officer Friendly cares about his fellow officers and since he never knows what item of minutia will solve the next big case, he's going to share whatever he's found with his fellow officers. That means his "Field Interview Notes" will most likely go to a searchable database.
Suppose Officer Friendly makes a note that he encountered a gentleman dressed in a white shirt, blue jeans and carrying a Glock .40. Two months down the road a bank is robbed by someone carrying a Glock .40 and dressed in a white shirt and blue jeans. Guess who is now a "Person of Interest"? Conveniently, they have your home address.
You're in the system, and once you're in you are never, ever, getting out.
If you are going to carry unnecessary identification when you don't have to (and I only carry mine when purchasing alcohol, buying airline tickets, etc) then I highly recommend everyone get a Passport Card. It's government issued ID and it doesn't reveal anything Officer Friendly doesn't need to know, such as your address.