Lol if you think banks are really "afraid" of Bitcoin. Do you know how easily they could spam the network for months on end? It costs them nothing.
the simply thing that they are interested in the blockchain technology without wanting bitcoin, mean that they are a little afraid about it, and they want to take the advantage of the benefit that this tech can provide, in the case bitcoin will be a good contender for them
Even if they aren't open about Bitcoin everyone is holding some. Even if they say "we are not interested in Bitcoin, we just want the blockchain" sort of thing, they are secretly holding lots of BTC, because at the end of the day the guys in the banking world aren't idiots, that's why they are rich.
i don't think there are enough bitcoin for every bank out there there are simply too many, so many of those bank simply don't care or they do not have any bitcoin, which are probably those bank that want to build their own crypto coin, like citycoin the last scam...