I have stated my position several times, but for those who did not see it:

* Cryptocoins are a great invention, and I wish that they succeed in their original goal -- a method of payment through the internet, especially across national borders, that is safe, cheap, convenient, fast, etc.  I wish that, and I would love to use them if and when I think that they are better for me than credit cards or other existing means.  I wish that, but I do not think that the chances are good. (One shoudl never confuse "desire" with "expectation".)

* I am not a libertarian. I believe that governments are useful and necessary, and we should fight to democratize and improve them rather than abolish them. I see the libertarians' idea of getting rid of governments as sheer lunacy. (For one thing, if you don't have your own strong democratic government, other people will gladly and forcibly lend you theirs.)  And I see their hope that bitcoin will let them build their utopia outside the reach of governments as lunacy squared.

* Adults have the right to do whatever they want with their money (within limits of law and ethics, of course), including investing it in whatever they like, gambling it, or even throwing it away. 

* In particular, I do not care care if someone buys a lottery ticket when he is fully aware of the odds, or trades it with some fellow gambler who is equally aware of them. 

* However, if I see someone buying a lottery ticket because he thinks it is a good investment, I feel this Darwinian duty (magnified by professional habit) to inform that fellow primate about the odds, expected value, and all that.  If the guy does not believe me, then, shrug,  that is his problem.  And, of course, I consider myself excused of that duty if  I think that the guy may steal my bananas, or if he snarled some unfriendly noises at me.

* Finally, when someone tries to convince others to buy lottery tickets, by telling them that it is a good investment, when his motive is actually to make a profit out of their "investment" -- then that guy is a scammer, and should go to jail.