UIT introduces the new property type 5 to represent non-fungible tokens. With UIT each token within a collection is considered a unique entity and can be addressed explicitly.
For example, a digital token could be created to represent cats. While the current protocol allows to create tokens to represent some form of cats in general, where every cat is a cat, each cat is also an individuum and distinct from another, so non-distinguishable tokens may not be sufficient. UIT allows to represent and interact with each cat on it's own.