Notification dots, unread badges, streak counters, and "someone liked your post" alerts are not information delivery mechanisms — they are pull-back mechanisms. Their function is to create an unresolved state in the user's mind that can only be closed by opening the app.
Kostadin Kushlev's research on notification interruptions found that even suppressed notifications increased distraction — the awareness that something might be waiting is enough. Przybylski et al.'s 2013 formalization of FOMO identifies the broader pattern: fear of missing a social moment is a reliable and exploitable motivator that apps can manufacture and deliver on a schedule.