Yes, visible transactions can be monitored easily. Yes, the blockchain is a globally visible ledger. As it is today, though, the blockchain does not lend itself to becoming an entity's ledger, because it cannot PREVENT postings. A hostile entity could send a little money to another entity's account and thus create entries unexplainable to auditors. A blockchain-based technology to support this prevention would have to be enhanced to require a transaction to be signed by the receiving account as well. There would be much benefit to such an augmentation: Anyone who claims transparency could easily prove it!