Source?
Also, do they do it only on Roku TVs, or even Roku devices like their sticks?
Note that this isn't documentation of their data collection practices, this is ad copy providing one example intended to convince advertisers to pay them. They mention TV but my guess is that this applies to every type of roku device, exploiting your data is how they make their money after all, although a stick is probably not capturing the screenshots in 4K. I would also assume that this applies to all content viewed on the device regardless of the app being used and including personal content cast to the device.
> We should note, however, that this data becomes aggregated, removing personally identifiable information before it is received by advertisers.
https://www.consumerreports.org/electronics/privacy/how-to-t...
The TV makers don't need ACR when you are using apps on their OS. Those apps all report the currently playing title to the OS maker. ACR is used for when you watch broadcast TV or anything coming in over HDMI.
The margins on TVs are surprisingly small, so being able to show you a few dollars of ads every year dramatically improves that margin, which allows the TV to be either a better value or cheaper compared to other sets you see in the store.
That would just tell them what show you saw. With screenshots they can see what was on the screen when you paused the show, what scenes you rewound and re-watched or fast-forwarded through etc.
For example, if you pause a movie on a scene with boobs, they can assume you like boobs. Pause a lot on screens with text, they can assume you're a slow reader (with how long you tend to pause the screen indicating how much you struggle with reading). Maybe you're the kind of person who has to go back and rewatch scenes with heavy exposition or you like to watch violence and gore frame by frame, or you skip through certain shows just to get to the songs/musical numbers. Pause/rewind a lot and it might indicate that you're busy/distracted, but also that you care enough about what you're seeing that you don't just let the content play.
Even if they already have the title of the show being played, not collecting those twice a second screenshots when they have the ability to would be leaving a ton of data on the table.
Furthermore, I'm not seeing whether they do this on their non-TV devices.
Edit: Seems the question is answered here: https://news.ycombinator.com/item?id=39950370
When I need to replace my TV, I will happily pay the extra 10s of dollars for one which will never do this.
Pricing an ad-free tier is a bit problematic. You would think that it should cost simply the ad-revenue per user more. However, since the more the ad free tier costs, the more advertisers would pay to reach those customers, the marginal ad revenue is higher. Someone on a hypothetical $30/mo ad-free tier has high disposable income, and is probably not being impressed by many ads already.