If there was a USD token that was near instant that may impact the market as you'd be able to run in and out of Bitcoin exchanges in a matter of minutes rather than having to wait for days on end.
There is no doubt that blockchain technology will make conventional banks better. But if these banks want to use a universal token in their banking system, they will have to use a popular one, that is bitcoin. It is difficult to create a new one and to agree within all the banks. This token should not be controlled by a single government.