How is it that they are aware that the changes are going to create not only questions but also doubts?
This is pretty significant. As you noted, the GB normally takes the position that they are to be trusted and their interpretations accepted under the threat of disfellowshipping. Yet here, they are anticipating pushback, but not taking their usual hardline stance. They seem to realize that they are taking a step that will be very controversial. Telling the KHs to close their bank accounts means they want every last cent going directly to the HQ.
And with what appears to be an automated online system of deposits, they'll also be able to know which congregations are being generous and which ones are lagging on donations. What happens when people figure that out? And how do you guarantee that unscrupulous brothers don't start to skim off the top when they are turning physical cash deposits into digital online transactions?