"The chip won't have ANY data other than "who" you are."

No it wont. It will only have a unique ID. That's not 'who' you are because it relies on a totally seperate system to link the ID to you. And that link is still precarious.

It's really no different to a plastic wrist tag with a bar code. The only thing it does is prevent physical tampering.

I can see that it may protect you from someone else tampering with your tag while you are incapacitated, but it also prevents you from removing your own tag...

*cue sinister music*