@StateObject and @ObservedObject are very similar in that they both keep track of an objects state. The difference is @StateObject is owned by the view it was created in where as @ObservedObject is owned by another view.
An example of when to use @ObservedObject is to keep track of external classes so the view can be updated when a change occurs. We would want to use an @ObservedObject for something like fetching new data from an API or a database.
We want to use @StateObject when we want the view to keep track of its own objects state. A example of how we would use @StateObject is if we had something like a number counter in a view and we wanted to keep track of the count as the numbers changed.
I hope this helps you better understand the difference between when to use @ObservedObject and @StateObject.
Thanks for reading and happy coding 👨🏻💻👨🏻💻👨🏻💻