I don't think its foolish to invest in bitcoin. But it is a risky yet good decision you can make. After all bitcoin is a money market and an investment that your money will work for you, you just got to be responsible and be patient at first for your investment to grow here.
Investments in bitcoin cannot be consider as foolish as this will give us huge profit in the near future if good strategies are implemented. For me investment in bitcoin is an opportunity for us to earn more.