Bankers are afraid that bitcoin will take over the whole investment platform that their investors are availing to them. And to take an action they are complaining to the government and as a body that maintains the balance to their entire economy they won't allow something that they can't control to catch the revenue that they are getting. So while it's early, they are taking short notice and also resulting to ban bitcoin if they can see it as a threat to the economy, and another reason is it's used by terrorist or money launderers though its another story.
Yeah more of this.