First of all, If we talk about the shortcomings of bitcoins, then this is a large volatility of the currency. In other words, even a month the price of bitcoin can make huge leaps. What is more, Bitcoins are still only accepted by a very small group of online merchants. This makes it unfeasible to completely rely on Bitcoins as a currency.

The most terrible dream for a person using Bitcoin will be the loss of a wallet.  If a hard drive crashes, or a virus corrupts data , and the wallet file is corrupted, Bitcoins have essentially been “lost”. There is nothing that can done to recover it. These coins will be forever orphaned in the system. This can bankrupt a wealthy Bitcoin investor within seconds with no way form of recovery. The coins the investor owned will also be permanently orphaned.

And, finally, Bitcoin has the signs of a financial pyramid with all its inherent properties: attractiveness of quick profit, high incomes of the first participants, extremely high difficulty in obtaining monetary units for new members of the system, etc.