I totally agree with your first statement, that a more useful virtual currency will spring up on top of Bitcoin for immediate transactions (I actually have a good idea of what it will be). Yet I totally disagree with your second premise. I think Bitcoin is a fine store of wealth. Fractional reserve banking and a debt-based economy is what many of us are trying to get away from. And I can definitely see Bitcoin as a long-term store of wealth and an easy way to make deposits into other, more convenient virtual currencies that are springing up.