For any currency to be viable, be it a decentralized cryptocurrency issued by a computer program or a traditional fiat currency issued by a government, it must win the trust of the community using it.Bitcoins are successful in it so banks are showing their interest.
Actually, the article argues that Bitcoin is a lousy currency/money (because of volatility and its deflationary nature), but could be a great store of value. Seems like everybody is discovering some good in Bitcoin.