Broadly speaking, blockchain is an ideal use case for the decentralized consensus on ledgers that are appended by themselves on agreed transactions that are non-commutative. In this section, I'm going to categorize blockchain use cases into a few categories; however, I believe that there are millions of use cases, which is the result of non-commutative state transition functions. The listed categorization of use cases is exhaustive.
Let's start by simply putting the definition of blockchain into an equation:
When is the timeline, while How much is the quantity. However, What, is the topic of discussion here. My efforts to categorize blockchain are centered on What and Who.
WHAT: What represents the assets; essentially, the scarce assets that are valuable. Assets such as identity, currency, land title...