Wow at that.
For one thing, getting prime time coverage of ads, w/o having to pay networks is pretty amazing but how it's done (Just the spin of it all) is just pure evil and that spin - I don't think any ads benefit viewers though.
They are selling you a below-cost TV and making it up in ads, same as Microsoft selling you a below-cost Xbox and making it up in accessory sales.
I don't think it's correct to say there's not benefit. The benefit of YouTube ads is that you have unlimited 4K content available for free (below cost of bandwidth).
While you may say you'll pay 600 bucks for that 55" TV with no ads, most consumers will disagree with you and they show it through behavior.
If most YouTube users were Premium subscribers, it would more than double revenue. Premium subscribers are worth more to Google than free ones are in ads revenue, by a lot. Monetized channels receive orders of magnitude more revenue per view from Premium subscribers than free ones.