You will then be able to trade futures contracts just like they are bitcoin spot. If price goes up on spot, a good futures exchange will have its contracts also going up in price, and then you can sell and get out. However, the price of the futures contract is dependent on others trading it. So if nobody else is trading it and bringing the market price of the contract along with changes in the underlying asset, then it's useless and you are forced to hold it until settlement to realize any of the profit/loss from the position.
Were Centra's tokens securities? Well, yes, obviously. We talked last week about the Securities and Exchange Commission's enforcement action against Munchee, an initial coin offering vaguely similar to Centra's in that it featured "utility tokens" to be used in a blockchain ecosystem that did not yet exist, sold on promises of speculative returns. The SEC brusquely and correctly dismissed the notion that such "utility tokens" were not securities, and I suspect any court will agree. Also, while Centra occasionally remembered to call its tokens "utility-based tokens" and "not securities, shares or investments," it often forgot. From the complaint:
Some Centra investors have their doubts, and a plaintiffs' law firm has brought a class action complaint against Centra demanding the investors' money back. The complaint is fun -- Centra had a “Blog/Media Bounty” program to "Reward Experienced Writers who write quality Reviews, Articles About the Centra Project and the ICO crowdsale" -- but not that fun, because the plaintiffs' lawyers don't actually need to prove that Centra was a scam. Their job is much easier: All they need to do is prove that the tokens Centra sold in its initial coin offering were securities. If they were securities, they were sold illegally: They were offered publicly without being registered with the Securities and Exchange Commission, or being exempt from registration. And one remedy for the illegal sale of securities is that the buyers can demand their money back -- whether or not Centra is legitimate, whether or not it is actually using the money to build a cryptocurrency debit card, whether or not it made any misleading statements in the ICO.
Making money arbitraging bitcoin futures can be extremely simple. Futures contracts typically trade at a premium, and all you have to do, starting with USD, is buy bitcoin at Spot price and sell futures of the same amount at premium price. Then just wait until expiration to make your arb profit in bitcoin (which you can then put in USD). Whether it's a weekly, monthly, quarterly, or any futures contract, as long as it's in a premium, you lock in the sale price and earn the arbitrage profit.