Youtube has already accounted for this by using a separate endpoint to count watch stats. See the recent articles about view counts being down attributed to people using adblockers.

Even if they hadn't done that, you can craft millions of bot-sponsored views using a legitimate browser and some automation and the current update doesn't change that.

So I'd say Occam's razor applies and Youtube simply wants to be in control of how people view their videos so they can serve ads, show additional content nearby to keep them on the platform longer, track what parts of the video are most watched, and so on.