Its price is not fixed so that it can not be used at the time of need.Bitcoin can not be made the main source of income. But when it is low prices in the market then it is better to buy and hold it.
I think you can depend on your future in bitcoin but not much, it is possible that the money you invest will increase and the value you will earn can satisfy what you really need. If you use bitcoin, then your future can lie on it, if you take bitcoin as the main source of your income then it will greatly determine your future.
Investing in bitcoin is good, but it does not mean that you have to invest all your savings / money, just make it a source of other income so your money will not stagnate and you can earn more.