Since you have to use an exchange to obtain or sell crypto currency, this 'advice' is just pointing out the terrible flaws in bitcoin/ethereum/whatever. There will be plenty of users who were in the middle of cashing in/cashing out and have now lost all their money, and you're just saying "it's your own fault"

It's just a sign that cryptocurrencies are new (and insecure) that I can't do the same with them.

For those among us that want to ignore the long history of banking and coinage in general, some depositors in greece may have recently seen similar analogues to why banking in a particular locale turned out to be a very bad idea.

Though you'll have people debate the relatively philosophical differences all day compared to the parties who have ended up on the wrong sides of the above.

What I'm more interested in is: how does all of this change the landscape of incentives of actors of all sizes, and what capabilities does it give to such that weren't accessible to such (or any) degree compared to before?

When I open a trading account on a stock exchange, it's not longer my money. I've loaned it.

I do have more confidence that its owners won't be arrested for money laundering, followed by all my funds dissapearing to a Bahaman slush fund, though.

In another thread (About the SEC regulating ICOs), there were a number of people encouraging investment into and downplaying the risk of unregulated, opaque financial securities ran by persons not based in the US. Rail against the SEC all you want, but events like this are why it exists. Fraud erodes trust in the market.