Hi Kristijan, pure functions handling business logic and smaller components are very useful software design concepts. Both also help to comply with a Single Responsibility Principle from SOLID. Each unit is doing its own job and has a single reason to change.
We strive to follow this in our huge codebase, too. Now with React hooks, we split it as follows:
This way everything is not just granularly separated and easy to test individually, but also very DRY (reusable).