Would you lend money to me and PAY interest for it? Certainly not. But that is what negative interest rate politics, practiced by many central banks, is asking for. As a result, banks are turning partly to "real world physical storage". The idea, negative interest rate would foster more investment, seems to be failing on a broad scale. This means: The ability to lower interest rate is limited by the cost of physical storage. Central banks are trying to push the boundaries by supporting the war on cash. They do not seem to take into account, that there will be a turning point, when conventional banks will give up their ideas against Bitcoin and will be pressed into Bitcoin and Altcoin storage, to avoid the price for real world storage. In fact, this is what already started to happen.
Banks are done for once bitcoin catches on