Banks do not have to constantly add more branches. Bitcoin MUST add more hashrate. The only reason someone doesn't have 51% hashrate today is because they can't physically get that much hardware at once. If miners don't keep constantly adding equipment eventually there will be a point where 51% worth of hardware will become relatively inexpensive to manufacture and launch.
Taking the article at face value, apparently bitcoin is not/no longer a solution for day to day transactions, but that it's true purpose is to facilitate international, inter-institutional, and inter-governmental transfers.
It seems to me that Bitcoin is a solution looking for a problem.