Comment by discovan

That's right! "Even though blockchain does not allow for modification of data, it cannot ensure such data is correct. The only exception is on-chain transactions, when the system does not need the real world, with all necessary information already being within the blockchain, thus allowing the system to verify data (e.g. that an address has enough funds to proceed with a transaction)."

However, I disagree that current money systems solve the problems solved by Bitcoin, but this is completely different discussion)