Banks use tools as a store of value by holding some assets in reserves, for various economic benefits. Although, adopting Bitcoin in such capacity, would have it's pros and cons. Obviously like controlling inflationary trends, and even help stabilize the volatility of Bitcoin to its users, and conversely such volatility could also alter the stability of a banks statement of financial position. All these could add up to a more stable global economy. Surely banks have started to think of such prospect
I what I like to imagine if bank held bitcoins is that of control. They will control who gets what and at what price. They will control it through the government. Bitcoin will be centralized and it will defeat the purpose of bitcoin. While I think some people like it because the see the bank as an institution that they can trust, this will mostly be older folks. The younger people strongly oppose it and will not support it from the onset.