The database doesn't have to be expensive to alter, that's a consequence of one particular type of scheme, proof of work, and there are already good alternatives or there will be shortly, with more coming. For use cases of a trustless distributed computer/database, see my other comment.
The database doesn't have to be expensive to alter, that's a consequence of one particular type of scheme, proof of work, and there are already good alternatives or there will be shortly, with more coming. For use cases of a trustless distributed computer/database, see my other comment.