Streaks create rhythm, while rewards make progress feel tangible....

https://source-wiki.win/index.php/Real-Time_Feedback_Systems:_Why_Your_Users_Need_the_%22Ding%22

Streaks create rhythm, while rewards make progress feel tangible. Personalization ensures content matters to you. These features turn scrolling into a habit. We build this responsibly with total transparency about how these systems nudge users.