I'm almost certain that the bandwidth cost is much higher than what they gain for recommendation algorithms. It's like saying "Yeah, that guy steals from your store, but at least now you know what's in demand!" (Not equating ad-block to stealing, just trying to show the value difference)

I really doubt this data is worthwhile considering their bandwidth and hosting cost.

Video hosting is at this day, almost a universal money losing scheme. YouTube is barely profitable, they need to make money, it is not even an option