Collapsing beats indenting once a document gets large
Indentation makes structure visible but it does not make a large document navigable. A formatted 20,000-line payload still requires scrolling past everything you do not care about to reach the part you do, and by the time you arrive you have lost track of where you are in the hierarchy.
A tree view inverts that. It shows one level at a time and lets you expand only the branches you are interested in. The top level of a 20,000-line document might be six keys, which fits on one screen - so you can see the shape of the whole thing before deciding where to look. That is a different and much better starting position than line 1 of 20,000.
Collapsed nodes usually carry a count, and those counts are informative in themselves. Seeing `items: [1,482]` next to `metadata: {3}` tells you immediately where the document's weight sits, without expanding anything.