Yes it's possible just holding btc could be more profitable(and it has been over the last few months), but it's also more risky because if the price falls by 50% your wealth falls by 50% where as holding mining bonds you would be better protected in such a situation.  Basically the reason you think mining bonds are turds is because you could put your wealth into something riskier and potentially profit even more - well duh but you're forgetting you could also lose a lot more if things go south too.