There's a difference between making money 50% of the time and losing the other 50%, and being right 50% of the time and wrong 50% of the time. You are confusing things my friend.

If you pick a stock randomly today and predict it will go up in the next hour without gathering much information about it, you'll have 50% chance being right and 50% chance being wrong. Now if you not only make that prediction but also put money into it, you'll have less than 50% chance of making money and more than 50% chance of losing money. Why? simply because you have to incur other costs in the process (i.e. transaction costs) and so you can only make money once the stock goes to a price beyond = (price when you invested + transaction costs + other costs).

The 50-50% odds you are giving would probably apply to the movement of a random stock in the market today, all else constant.

Now if on the other hand you pick a stock that is affected by a recent news (just like Bitcoins after the Chinese government's news) there will be more than a 50% chance the stock in question will go down in value if the news is negative and more than a 50% it will go up in value if the news is positive. I would confidently say the stock will go down at least 90% of the time if the news is negative and  up at least 90% of the time if the news is positive. Now off-course this will not go on infinitely, there's a time window when this will occur (but that's another topic).

So you tell me, if that's the case and it's that simple, then why don't most people make money trading right after news come out? there are a couple of reasons:
1- They find out about the news or act upon it once its too late (once the value adjustment has been made), and this happens much more quickly in mature market like the NASDAQ or the NYSE.
2- They perform the trade at the right time but the transaction costs offset the possible gain they can be making in the process. Why?
   - Because in mature markets stocks are less volatile and so move in a lower magnitude than new markets. That is to say that while Bitcoin might lose 40% of its value to a negative news, for a mature company the loss in value might be 1 or 2%, and so the transaction costs are high compared to the gain they could be making, which on average would cancel out the gains that are made in the process.

The reason to the above explanation has to do with an economic phenomena that says the following: In a system where there are enough players, and where information is equally available to everyone at the same time, opportunities cancel out. It doesn't mean that opportunities don't exist at all, it just means that opportunities don't exist on the long term. Meaning that if you are among the fastest 1% of people who short the stocks of a company after bad news, then you can make money in the process, but you can't beat the market all the time. Sometimes you'll beat the market and sometimes the market will beat you, and so on average it's a zero sum game.

This is why they say mature markets are efficient. Efficient in the sense that as long as money can be made, new players will join until the market reaches equilibrium (gains = losses).

What's different about trading Bitcoin? The only and most significant difference is that the economic conditions discussed earlier STILL don't apply. Meaning that not enough players are playing the game, or not enough players have access to information. By not enough players I mean, an amount of players that is not sufficient for opportunities not to exist. Those opportunities may disappear if more players join and the market becomes more liquid and less volatile. But for the time being, it's not the case. And this exactly, is why I said actively trading (in a rational way) might work in your favor for now ( because equilibrium is not reached yet).