Ok, we changed "collect" to "detect" in the title.

Yes, it would be crazy if it could collect history. But it can be used to target ads much better and create user "profiles" (and track users by cookies on a network of websites) and for example much better target products on an e-commerce website... It doesn't have to be used for evil, but it certainly can, and can be automated.

This vector has been known for many years.

And has been largely fixed for several. See e.g. https://developer.mozilla.org/en-US/docs/Web/CSS/Privacy_and...

Actually it's not using the JavaScript for checking the link color and instead is using a timing attack, so that link makes no sense.