Two common patterns where the developer wants to specialize to a single object usually emerge after extended usage. First, there are domain objects which naturally have special non-sharable behavior. For example, True is clearly a particular object that helps define the semantics of the whole system, by representing mechanical truth abstractly. In other situations, the same pattern occurs where one has a universal concept, or locally an absolute concept within a domain.
Second, there are situations whether the user is demonstratively modifying the behavior of some thing in order to achieve some prototype that behaves in some situation as they desire. Depending on whether the user decides to share this behavior or not, the instance-specific behavior may or may not migrate to some shared Traits object. In either case, this is an encouraged use of objects and methods within Slate.