I think that "Bergsteiger's" sistem is very fine. Climbers might find it stupid as why to rate hikes, which are even not climbs. But also usual hikers want to know the difficulties and their competencies vary a lot. As you saw, the category of hiking would end where the category of climbing starts, but there's some overlapping. Also us, hikers can cope with easy climbs up to degree UIAA II, and that's the upper part of hikers' scale.