Otherwise blockchain is just a fancy database. Normal centralized databases are simply files located on a single server. Or few servers, but only for backup reasons. There is one owner of the database who can change it every time he wants, he has the control of the data. In blockchain we don't want anyone to exclusively control all the data and that's why it is designed as a decentralized database - database that exists on many locations at the same time, but is designed in a way so that any person owns only small fraction of it - his own address.