A blockchain is nothing more than a public ledger, a system of checks and balances. It can be used to store any type of data, including but not limited to-- biological/genetic information, private encrypted data, 'currency' and a plethora of other options. Check out some of the interesting ICOs and where they are taking the idea of the Blockchain. Many of the 'tokens' aren't meant to be 'coins' at all.. but rather, fuel to drive a new decentralized system.