These are all speculation. I'm not no expert on bitcoin, but this is a somewhat stream of consciousness on the area that most concerns me. Bitcoin could suffer

These are all speculation. I'm not no expert on bitcoin, but this is a somewhat stream of consciousness on the area that most concerns me. Bitcoin could suffer an implementation derived security attack, ruining all practical value. The math behind bitcoin may be rock solid. However the implementations of clients on p2p network are vulnerable to security attack. If bitcoin begins to transition to mainstream and something like SQL Slammer hits it, a rival crypto currency, or a big company derived alternative will replace it, assuming crypto-currency as a whole doesn't garner a three-mile island like reputation. In its current state Bitcoin could fall to this from simple lack of UX. The technical complications around securing a bitcoin wallet could leave people with bitcoins they don't realize have been stolen and transfered until they attempt to use them to pay for something. I know bitcoin has strong cyptography behind it. That is a building block for secure software. There is however a world of difference between the mathematical tools used to secure something and software that is secure in practice and use. To me the highest risk area is how hard or easy it is for non technical people to use correctly, and how hard or easy it is for unscrupulous people to harm non-technical people who are trying to use it.