By applying some simple architectural design patterns to your mobile code base, you can greatly reduce bugs, isolate complex or fragile code, and maximize your development time by making your code simpler to read and easier to test.
First, it simplifies the code any one class contains and breaks them into single responsibilities. This is for both writing the code, but more importantly, it simplifies the reading process.
With even the most basic architectural elements of separating our layers, we gain this benefit of simplification. Because pieces are broken into their single responsibilities, we also can avoid bugs and isolate our complex or frequently changing pieces of code into their own separate areas.
This makes it so that developers can treat these as black boxes that are simple to use with their proper APIs. As your app and team grows and allows developers to specialize in areas they enjoy or feel comfortable in such as UI concerns, or perhaps there's a developer who loves the database or the network endpoints.