The difference is with a blockchain system every individual actor pushes in the transactions that update the data, whereas with the existing system you have to trust an arbitrary central party to perform the updates.
The problem with existing systems is that the incentives of the entity owning the asset and the entity responsible for updating the database are not aligned.
If you don't trust the company you're investing in and the securities regulator to record things faithfully on a non-distributed ledger and uphold the law, update privileges to and mutability of the transaction record is the least of your problems when it comes to investing.
The problem with existing systems is that the incentives of the entity owning the asset and the entity responsible for updating the database are not aligned.
Sure they are. An exchange is a combination of some physical systems and credibility. People won't trade on an exchange they don't trust.
The problem with existing systems is that the incentives of the entity owning the asset and the entity responsible for updating the database are not aligned.