I think that Bitcoin can be use as a matter of fact to be globally accepted. What is your take and which currency can you suggest to be accepted globally?
I really don't think that bitcoin can become main global currency, replacement for other currencies.
You see, if you pay for some service with fiat money, and somebody deceive you, you can complain to the authorities and you will receive your refund eventually.
With bitcoin, you can't find out real owner of btc wallet and can't complain to the authorities and request refund.
Because of it, banks or financial institutions will never accept bitcoin for their business.
Bitcoin have future only as alternative to the traditional money.