It logs requests to the site, which is far less invasive than the fine detail of browser fingerprinting and tracking that JS allows: JS can see your mouse pointer's position, how long you spent on each area of the page, which parts of the text you selected, and many many other things.
You can implement similar mouse recording via requests for :hover psuedoelements in CSS. Also, I’m not sure you need JS to get fine fingerprinting and tracking in 2020— https://wiki.mozilla.org/Fingerprinting
Legitimate tools for measuring effectiveness of pages with little in the way of nefarious tracking afaics. Also very useful for replaying user errors/problems.
There are many companies with similar products: Inspectlet, Lucky Orange, probably more. This is a cat that will be quite difficult to put back in the bag.
Things like this are seriously creepy: https://www.crazyegg.com/blog/mouse-recorder/