I assume it's driving engagement with people in general, but it inhibits my engagement.
Which goes back to one of my perennial frustrations with all this tracking and A/B testing bullshit; they're tracking my every mouse movement, they're slicing and dicing pennies in an effort to advertise at me, but when it comes to something I'd actually like, like them noticing that not only do I not "want" these autoplaying ads but that they actually decreased the very metrics they care about for me, suddenly our monstrous tracking machine with seemingly endless resources to stare at me like Sauron's All-Seeing Eye goes all blind on me.
It's extremely noticable in the roku app. It pauses for a couple seconds every time you navigate so you can't really do anything until the autoplay loads. You end up seeing a few seconds of it for every single item you hover over.
I can't stand though when it autoplays trailers or previews or automatically starts something new when i've finished something i'm watching. Scrolling through netflix and having things autoplay as I scroll through is annoying as all fuck.