It's difficult to overestimate the learning curve for any technology. That's why effector provides you few simple examples that may cover your basic needs and also give more confidence for the users for upcoming projects using effector.
To display loader during effects resolving
We'll need it when second request to the server requires resolved data from the first one
When we need to cancel our effect since it's pointless at the time
To connect react modal with state
To connect custom range input component with state