We called this structure a hive, in honor of the Windows registry -- always a good role model for software design. We wanted it to be as simple to use for new data as possible, so we could just plow forward with new code and never think about how the settings were being saved. If the setting became important or significantly-used, we could move it, later, to a more strictly-typed part of the schema. For now, the goal was to allow for rapid development.
Hives are a nice twist on narrow table/extradata storage.