I wonder if the supply of Bitcoin is enough for us? If people all over the world use Bitcoin for daily payments, what will the prices be like? Are global prices the same?
The privacy of Bitcoin protects our personal safety very well. Although I would love for Bitcoin to become a global legal tender, I don't think it is realistic.

    As an amusing thought experiment, imagine that Bitcoin is successful and
    becomes the dominant payment system in use throughout the world. Then the
    total value of the currency should be equal to the total value of all
    the wealth in the world. Current estimates of total worldwide household
    wealth that I have found range from $100 trillion to $300 trillion. With
    20 million coins, that gives each coin a value of about $10 million.

    So the possibility of generating coins today with a few cents of compute
    time may be quite a good bet, with a payoff of something like 100 million
    to 1! Even if the odds of Bitcoin succeeding to this degree are slim,
    are they really 100 million to one against? Something to think about...