Simply put, a blockchain is just a distributed ledger. You can record data in a “block” and it can’t be changed later on.
While the most common use of a blockchain is currency, that doesn’t mean it’s the only thing it can be used for. You could use a blockchain to keep track of any type of data/transaction you choose.
We have that already. Its called a database. The incentive to secure the network for a cryptocurrency in an immutable structure is the mining reward.