I think the difference is that with stocks and related funds you can put some numbers behind the movements.  If earnings go up then generally the stock price will as well.  BUT interest rates are sure to go up soon which should have a negative impact on the price of stocks.  Also corporate earnings have been lowering.  I think that in the short run buying any stocks has a lot of risk because the market is generally overvalued. 

Bitcoins on the other hand are really hard to predict.  I think it can basically be boiled down to how much money is coming in or going out.  This can be really hard to predict with any accuracy.  Past performance of a CEO for a stock can be a good indicator that he will perform similarly in the future.  A company producing good can be researched.  You can find out how much demand there is for the product.  For me bitcoin is more mysterious. You never know what will happen.  As an investment I think it is a high risk-high reward kind of game.  If you hold them long term and they are still around in 10 years then bitcoins will almost certainly be worth a great deal.  But on the other hand you just never know what will happen in the future.  It is risky and as others have said the best thing to do is diversify.