Investing in bitcoin is a clever decision now because very soon it's price and demand will increase as both are directly dependent on each other. So if you but bitcoin and hold got 6 months then also you could get $100 just by doing nothing but hold your $800. I think it's not a bad idea
It is not anything "clever" but rather a general idea. Many people like us are holding bitcoin and selling them when prices rise. Then we buy more when prices fall and in doing so we are making profit. Its called trading and its very popular among cryptocoins. One of the biggest reasons for which bitcoin is used nowadays is for trading because the big price of bitcoin with respect to fiat is what draws the crowd of traders towards it.