This paper presents the results of a in-depth qualitative study to investigate if and how our previously proposed Cultural Viewpoint Metaphors (CVM) can support practitioners in assessing the quality of HCI design alternatives. The results of the study underline the epistemic value of CVM in cross-cultural system design processes. The metaphors have not only helped participants to organize their thinking about how cultural diversity is exposed and communicated through systems interfaces, but also to build new knowledge and understanding about culture itself.