Most of the time, an outliner is used as a simple database - you want to store information in a tree, so you know where to find it. How annoying is it then, to have to swap to a different screen to find that information?

The entire point of this is to allow you quick storage and retrieval - you have a tree of information that you can manipulate, but with a split view, you can also see the information associated with each item, and just by touching it, change it.

The splitter is movable, so you can choose how much space the tree and the data take up