Yes and no. Metadata is more than just tracking info. I did mention watch history, likes, and mouse position, which are not things that can really be blocked. This also includes things such as how likely you are to click on a video based on thumbnail and screen position, how long you watch specific videos as well as how long your overall watch train is. They know what they’re showing you, where it is, and what you click and when; that’s enough to provide a hell of a lot if data. All in all, how you actually use the service is something that they pay very close attention to, and is still very valuable.
Is it as valuable as tracking info and advertising, definitely not. But it’s far from worthless.
Because you aren’t an individual to them, you’re a statistic providing them with valuable market research on how their service is used.
“People that watch this collection of video classifications are more likely to watch videos who’s thumbnails have these characteristics. Only 1% of them use ad blocking so we can improve our ad presentation rate if we present more videos with these thumbnails to this group.”