• Optional/nullable data types.
• Variant data types.
• Flag with extra information needed only in some cases (or different in different cases).
• Modeling states in a state machine where each state can have some data associated with it.
• List of operations for batch processing, where each operation can have its own arguments.
• Alternative to function overloading that allows avoiding combinatorial explosion when there are multiple parameters that need variants.
• Nested data structures with heterogenous nodes.

If you're reading this, you probably suggested to somebody that a particular technical problem could be solved with a blockchain.

Blockchains aren't a desirable thing; they're defined by having trustless consensus, which necessarily has to involve some form of costly signaling to work; that's what prevents attacks like sybil attacks.

In other words: blockchains must be expensive to operate, to work effectively. This makes it a last-resort solution, when you truly have no other options available for solving your problem; in almost every case you want a cheaper and less complex solution than a blockchain.

In particular, if your usecase is commercial, then you do not need or want trustless consensus. This especially includes usecases like supply chain tracking, ticketing, and so on. The whole *p