If you think that Bitcoin which is driven by purely supply and demand is a scam and a big Ponzi scheme then you must also say that all things on the market and stock exchange are pretty much a Ponzi scheme since they are also driven by supply and demand.  If you wanted to take advantage of the Bitcoin market, you need to consider your intention and why you are buying Bitcoin.  If your goal is simply to get a profit in a short amount of time I think investing in bitcoin won't meet your expectation.