Bitcoin has been touted as a crypto-currency, capable of replacing fiat currencies but the reality today is that most people prefer to hold bitcoins rather than spend it. Can we really say it si a currency when a large number of bitcoin users treat it as an asset?

Cash is the most liquid asset, while real estate, fine art and collectibles are all relatively illiquid.
http://www.investopedia.com/terms/l/liquidity.asp