Money & WorkFact
The app is free. Your evening isn't.
Free apps don't sell to you, they sell you: your attention is auctioned to companies as ad space, and your behaviour is turned into profiles that make ads hit harder. The longer you stay, the more the provider earns. That's why feeds are endless and notifications are pushy.
Useful: Ask of every free app: how does it make money? The answer explains its design.
Source: de.wikipedia.org