In theory the unique id produced by the scan could be salted by you, uniquely for each website or application, and then provided to the site. This would keep aggregators from being able to track all your activity, or at least it would if they didn’t already have fingerprinting techniques that do it without the need of another unique identifier.

The need for privacy in crypto is significant and a hinderance to wide adoption. With most crypto if you send me money once I then know your wallet address and I can then look up every transaction you’ve ever made with that wallet and every future transaction you make later. Clearly that’s a problem.

The fact that criminals are more motivated by privacy concerns doesn’t reduce the need and expectation of privacy for the rest of us.

To hear you say “Hey Google” it has to listen to everything you say, all the time. While they pinky-promise they aren’t doing anything with all the voice data they’re getting while listening, do you trust them?