How do I choose between app development and atomic service development?

Applications and atomic services are the two service forms of HarmonyOS. You can select either or both of them to develop based on actual service characteristics.
Atomic services are more lightweight and easier to reach users, providing smooth user experiences.
Atomic services also boast for fewer workloads and easier development than apps, owing to the advanced API set.
Atomic services provide multiple shallow entries at the system level to help partners efficiently distribute services to users, implementing multiple message capabilities to reach users.
In the same service, apps and atomic services can complement each other. Apps focus on the acquisition and conversion of private domain traffic, while atomic services focus on reaching more users in a more precise way through HarmonyOS service distribution.