There has been much discussion about the potential of blockchain, the technology underlying virtual currencies like Bitcoin, to change the world. We have heard waves of inspired commentary on how the technology, with its ability to share information and record transactions, will be as revolutionary as the internet itself. At Accenture, we agree about these huge possibilities, but there is an elephant in the room that will need to be confronted.

One of the accepted virtues of blockchain is that it creates a permanent, immutable ledger of transactions. For example, each of the roughly 160 million Bitcoin transactions that have occurred since the cryptocurrency began in 2009 will stay on that ledger as long as Bitcoin exists.

That permanence has been vital in building trust in the decentralized currencies, which are used by millions of people. But it could severely limit blockchain’s usefulness in other areas of financial services relied on by billions of people. By clashing with new privacy laws like the “right to be forgotten” and by making it nearly impossible to resolve human error and mischief efficiently, the blockchain’s immutability could end up being its own worst enemy.

The financial services industry needs to face the question of how to balance the appeal of pristine accounting with the demands of the real world, where some things simply need to be struck from the records.