Why Use Blockchain

Blockchain is just an ecosystem which is made up of consumers and hosts in which all of the data is public and each of the transaction is evaluated and authenticated by multiple nodes and then they are publicly posted into the blockchain, once anything is posted over Blockchain network then it couldn't be manipulated. This is the major advantage of blockchain- Transparency and Security.

The whole Blockchain ecosystems is based on Hashing and encryption of the data which leads to the immense security and integrity of the data

For more , please read the Bitcoin White Paper which is written by satoshi nakamoto