A few years ago, fake antivirus popups would appear, and you could get browser hacks of Chrome which would go away if you closed Chrome, and restarted the machine. These have stopped.
A possible risk he doesn't mention is illegal content being placed on your computer.
Update (same day):
YouTuber TekkitRealm says he learned about a lawsuit against him and his channel for exposing a hacking operation; he found it in his spam folder (which could mean the email is fake and more makware), link.