I must admit it is a sound plan. Instead of turning back earned BTC to everyone, the Stakecube has converted owed tokens into debt tokens. Even though they claim they would eventually buy back these tokens at 1:1 ratio (unbinding promise), I would bet the Stakecube will buy some tokens from the market.
Would I be worried if this scenario would turn out to be true?
Hell, no. If the bought debt tokens are irreversibly burnt, means the Stakecube did pay off some debt for fraction of its value. What is also important, it wouldn't happen 'forcefully' like in case of structural insolvency where everyone is forced to accept being paid less than actual amount of money owed. You can wait and hope on this promise to be fulfilled or you can try selling your debt.
Win-win for me, considering the situation in which we have all Stakecuber's find ourselves in.
