There are many differences of bitcoin and real money.. bitcoin you can use it online as alternative real money you can buy anytime there.. in bitcoins you should have too because many other will exchange it fast and instanly in our place.
Same here though, Bitcoin help us to invest money or rather to say save money to make it grow or increase it price, Bitcoin is the only one currency where bitcoin money can be easily converted into a real money while real money is the one that sustain our needs everyday we use it usual than Bitcoin money.