It might be able to identify a unique user but not the user personally. I think there’s also a fairly broad margin of error in how accurate it can identify a unique user.
a) Techniques like this can identify a unique user to 99.5% accuracy e.g. https://fingerprint.com
b) It can identify the user personally because many web sites use pixels where we link the fingerprinted user to an email address and then send both to Meta, Google, Reddit etc. And since browsers like Chrome allow long lived first party cookies this works because users remain signed in for over a year.
