One thing to remember is when you are away from home with your pet, having emergency contacts can be hit or miss.
I often camp where there is no cell coverage. In addition, it may be a long way from home.
If my dog got lost, a micro chip may not be checked for at least a day maybe longer. A tag may get that number called sooner, but you may not get the message until you've driven back into an area with cell service.
Having an old fashioned barrel tag IN ADDITION to the others can allow someone to drive the dog directly to your campsite while you are still there.
Also, as I get older, I think of other precautions:
Keep a paper with a description, age, sex and name of your dog(s) on your person. If you collapse while hiking, etc., that paper can get your dog back to you if it runs off scared.