This discussion would need to be broken into 2 types of blockchains: public and private.

A public blockchain with a token based mining system is where the greatest potential lies. A private blockchain is somewhat like an intranet where a public blockchain is a full-blown internet.

The Bitcoin currency (a system with a public blockchain) and other cryptocurrencies will obsolete fiat money. So that in itself is a very powerful commercial application. All of the world's money will eventually make the transition from obsoleted currencies onto public blockchains.

As banks make this transition, they will provide new services such as keeping the private keys for their customers. As for private blockchains, they will have real-world application, but in some respects they are simply glorified databases.