We dont need bitcoin because it is a electronically currency, we should not trust banks and governments blindly. Well i suppose put a lot of money in any man and he might turn into a greedy monster. So the problem itself is our human nature, we are so damn greedy and if we dont want more, we want control, which is what the banks and govn has accomplished so far. Since we cannot fix our greed and desire for more, what we could fix is the trust system, which only (as of now) possible through btc and blockchain tech.