Can you imagine a brokerage in the US being able to say that the underlying is 'designed to increase in value' or that it's value 'decreases occasionally'? They couldn't because it would be illegal.
Bitcoin does not represent the assets of any enterprise. Currencies have their value pegged (at some point) by a soverign which Bitcoin doesn't have. Bitcoin is designed to float (which means rise to the top) amongst other currencies. That is axiomatic of the design of cryptocurrency, not merely a prediction.
What you are saying is completely irrelevant. If bitcoin was traded on a futures/forex firm's platform, it would be illegal for them to make this statement. Forex firms cannot make these types of statements. An exchange or brokerage house cannot make statements regarding future performance other than there are no guarantees and that past performance is not indicative of future results. A systematic managed forex fund is 'designed to go up in value', but if I stated this, I would be summarily shut down. If this isn't obvious to you, it tells me that you have little professional financial experience because this is a basic, cardinal rule.
Gox is unregulated. These statements, in addition to the bizarre pricing action on their exchange, make me question everything about Mt Gox. Were there ever DDoS issues?