No monetary system is perfect. Bitcoin too has its flaws. I have two primary issues with BTC.
1) Its value is derived purely by supply and demand in the market place. It is like a piece of art. It is only worth what someone is willing to pay for it.
2) What's to stop a wealthy consortium or a country like China from taking control of it. And if this were to happen, since it is not backed by anything physical, would its value fall to zero?