Fiat will dissapear but not the banks because they can easily to shift from FIAT to Bitcoins. Parts of histories about banks they will receive goods and merchant to be use on trade before, silver and gold as well are receivable until it become paper money or a fiat now, so it is also possible from fiat they will shift to bitcoins as long they can gain from collecting of fees and interest specially banks are already use to digital transactions in which bitcoin is a digital.

Just follow the basic method for trading which is buy low and sell high. But I do suggest that you have to buy low thrn just hold it for about three to five years from now. Do not participate in gambling or investment sites that could waste all your Bitcoins or even lost it with just a blink of an eye. If you have a tight budget just like mine much better you have to participate bounty campaigns of you are a newbie, signature campaigns if you are jr member up or you can do trading too if you have enough skills or ideas, methods and strategy. In my case I only earn Bitcoins by participating in signature campaigns for me to give additional long term investments because I hold all my Bitcoins.