I am going to suggest another couple of reasons to invest in cryptocurrencies. Altcoins are in the wild west phase of investment. At this stage the mechanisms that are in place in the stock market do not exist on the exchanges. In essence you have simple transactions of buy and sell. Of course some coins are pre-mined but people can factor this into their buying decisions.
On the other hand, in the regular stock market there are preferred traders who are able to purchase shares at a lower price before stocks are released on the market. When the stock is released on the market, these preferred traders have already made a profit.
In addition, there are no governments actively trading in cryptocurrencies (that I know of) yet. Occasionally a whale appears in the markets but not like a government which can out-compete everyone to influence the rise or fall of a specific commodity. The paper price of gold for instance has been suppressed by government interference. An article in Forbes (July 7, 2013) by Todd Ganos states:
According to a report released by the Federal Reserve
last week, the M2 money supply is about $10.5 trillion. The amount of gold held by the United States government is approximately 260 million ounces. Doing the math, that translates to north of $40,000 per ounce. This is too difficult to even comprehend. But, whatever the real number might be, it seems that it is above the current $1200 area that gold in currently trading.
The paper value of gold is manipulated by future contracts at the London Exchange.