All the apps nowadays include some sort of list one way or another. Whether the main view of your app is a list or not, one common use case is to have a list displaying multiple types of items. Then you look at the examples provided by Google and they just show some simple case where you have a plain list with no variation between its elements, which is a valid case but not so common as apps get more and more complex.
This tutorial shows you how to achieve something like the following picture with a single ReyclerView adapter:
Read the full article: https://javiermendonca.com/using-different-viewholders-in-the-same-recyclerview-adapter/