It would reduce the variability. 1 in 200,000 is reasonably unique. But if all Firefox browsers reported the same result for fonts, then it would provide no more information than the spying website already has (i.e. the user is using Firefox).

I'd bet that Chrome would follow quickly, which would put pressure on Apple to do the same. If that happened, we'd have a minor victory.

All I'm trying to do is reduce information that is needlessly leaked out by a browser. True privacy still requires more.