You are right. We should not depend our future on bitcoin as its price is volatile. We are not sure on how it will be priced one to two days or years from now. That is why I am just investing the money which I can lose. Those are my extra I guess. But would be hoping that its price would goes up to secure my future. 
Yes, because we didn't know what happens on Bitcoin soon or in the future much good to invest the what you can afford to lose, Investing on bitcoin is just for extra income much better you have a real business than focusing on Bitcoin 
Bitcoin is good but we can't handle the situation what happens next month or years on the market and as you see now many new investors loses their capitals due to bitcoin drop.