I would also add to my #85 that in some circumstances where a dog becomes separated fro it’s owner and a dispute arises over ownership or identity like happened here in Louisiana after Katrina, or virtually anywhere dogs are “dog-napped”, a thief or would-be owner can easily remove a tag and lose placing the dog’s ownership in question. A chip...not so easy, and certainly a means of very positive identification.
My little doggie got out the other day. I had completely forgot she had been microchipped. A lady took her to a private pound which just happened to be where she was adopted to see if she had a chip and they rang me up. From the time she got out until the time I got her back was less than two hours.