For me both will be possible.If government and banks accept bitcoin,the people will be regulated by it and it can cause a centralized currency,because a third party is present on it.The more the regulation the more it can be centralized.
Well but anyhow behind it.. most of the countries governments still thoughts it will disturb the country's financial system, and worried for a variety of certain reasons. But it's also possible.. in over time the most governments of each countries will insist to accepting if bitcoin is more directing to a more positively things that can advance the country and its citizens in economic life.