By taking the debenture, you get the fixed return (again, assuming it's not a scam for the sake of argument) and you keep 10% of the shares, which would participate in any low(er) float runup.
And if you don't take the debenture, you're left with 100% of your shares, while many others have only 10% of theirs. Effectively, those who opt to accept the deal are accepting a de facto r/s. Those who don't accept will not be subject to that.
This is a real no-brainer.