The obvious and most common is asynchronous state that has some associated loading process/time. Especially those situations where loading some top level object implies to start loading a collection of lower level objects.

Reacting to object changes (persisting them to a database, or otherwise audit logging them).

Kicking off and managing "background tasks" like chron-job equivalents (5 minutes after a state update do some other related thing, such as a automatic state machine transitions), database synchronization/replication processes, cross-checking/merging in data from GPS/geolocation/compass streams, etc.