Types are a useful design tool to explore the problem domain first, while the rest are details that emerge from that. Sure, if one starts with architecture, you

Types are a useful design tool to explore the problem domain first, while the rest are details that emerge from that. Sure, if one starts with architecture, you're right. The software architect needs to consider these first. The programmer on the other hand ideally expects those as inputs. When tasked with wearing on multiple hats (architect, programmer, user), I agree with your point. From a programmer's point of view, however, (abstract) types are IMHO indeed a much more useful tool as they cover many of the other concerns (policies, performance, etc.), too.