Hi Patrick,
I am not exactly sure how these hierarchy views are used, but if you look into the Analytic view activation log, then you may find the statements like:
Create hierarchy view: CREATE COLUMN VIEW "_SYS_BIC"......
TYPE hierarchy WITH PARAMETERS ( 'hierarchyDefinitionType' = 'select','hierarchyDefinition' = '{ "runtimeObjectType":"blob","sourceType":"leveled","nodeType":"string","nodeStyle":"levelName","rootNode":"(all)","sourceQuery":" SELECT DISTINCT ......
It seems that the hierarchy view is created from the distinct values of the Analytic view columns.
Why are these created and how are these used, is something SAP elites should be able to explain. 
Regards,
Ravi