Bitcoin is designed to store value and/or appreciate value.  Some have mentioned above how the rate of manifestation of Bitcoins is growing so much slower than the adoption and demand for Bitcoin, and is the situation that is leading to Bitcoin's rapid appreciation in value.  That appreciation affects human behavior and so we hoard Bitcoin rather than trade freely with it.   This is not a weakness of Bitcoin, simply the way it is designed.  It's purpose now, whether we all like it or not, is "value storage" not "trade facilitator".