Lots of hype, tarnished by crypto-libertarianism and Bitcoin, but interesting technology nonetheless. Distributed ledgers of one sort or another could be used for beneficial purposes (see e.g. DisCOs).
Both blockchain and digital currencies offer a great deal of potential, but Bitcoin itself is a deflationary, capitalist medium that functions primarily as an investment asset to concentrate wealth, and is mostly favored by right-libertarian hard money ideologues.
However, the really interesting point about Bitcoin is not the currency itself, but rather the fact that its protocol – the blockchain – can be used to implement many other applications which have nothing to do with money.