If just for the fact that it annoys people I love the mouse cursor idea. But I also find it technically interesting. Is some kind of consent legally needed per GDPR or something for this? I for sure is tracking, literally. And a website has to ask to set cookies ...
Cookie consent is only necessary if you're sharing it with others (eg. ad networks, Google Analytics, etc.) or using it for "non-essential" functions (again, stuff like analytics). Sites just don't want the general public to realize that. As for the mouse cursors, I don't think they qualify as personal information under the GDPR, but IANAL.
Regardless, I don't think it matters since the author is not in the EU.