The problem with that is that indentations within indentations are just obnoxious. It is far from uncommon to add an item at the wrong level in a large config

The problem with that is that indentations within indentations are just obnoxious. It is far from uncommon to add an item at the wrong level in a large config file. Worst is when you have a large file that is showing several meaningful lines of indentation on one screen, where the roots of several of those levels is not visible.