It also: - Acts as the primary mechanism to make the data in the chain immutable, as the cumulation of the work (chain of valid blocks) becomes harder and hard

It also: - Acts as the primary mechanism to make the data in the chain immutable, as the cumulation of the work (chain of valid blocks) becomes harder and harder to reproduce. - Anti spam, i.e. you need to put something at stake (electricity and hardware cost) to participate in the issuance and transaction ordering