It's highly unlikely they obtained 17 billion samples, so they're likely guesstimating it by assuming each attribute is independent, and summing the entropy of all attributes. That's obviously incorrect, both because attributes are inevitably going to be correlated (eg. ip geolocation correlated with time zone), and that two identical devices (eg. 2 iPhones) will have identical fingerprints.

It's unique but changes on each reload. While the details are interesting, the fingerprint itself is not useful.

And I get a different id every time I reload.

I have the exact same, Unique to 1 in 17,179,869,184+ devices. actually slightly different. hmmm... ,'s vs .'s