Cash is better than bitcoin because it is acceptable by everyone, easy to use and easy to transact. Bitcoin is far compare to cash, but i believe that someday btc will use a main way to transact online. Investing your cash with bitcoin today will surely help you achieve your goal in life.
Of course cash is better now because cash is used by all people in the world so cash is accepted anywhere. Different from bitcoin that is only used by some community in the world only, maybe bitcoin will be better than cash when bitcoin has been accepted anywhere as done by cash, is it possible?