I've noticed a tendency to superimpose ads over the screen in US TV shows now. Crazy Ex-Girlfriend does it a lot and it's o annoying.
Except when it is hilarious.
During an episode of Once Upon a Time, there was an ad for the Wonderland spin-off. The White Rabbit is pointing at something (the title of the show maybe?). But what he is specifically pointing at is actress Ginnifer Godwin's (Mary-Margaret/Snow White) crotch. And I believe there was a slogan, something like "its right here" or the like. This caused such an outpouring of wtf on social media, an ABC exec (or show exec - again its been a while) had to issue an apology the following day.
I didn't watch the episode until after I'd read the article, and I still laughed uncontrollably at the poor ad placement.
Seriously though, the reason for it - and the network logo, show name, etc. - on the screen is to make the show less desirable. Also why the credits are rendered unreadable. All to encourage you to buy a copy to see it unadulterated.