Once a bond gets this distressed, it tends to trade at its estimated recovery value (whatever bondholders might receive from the bankruptcy process). The current price of GREEL at ~4 cents on the dollar implies a very low prospect of recovery. Granted, the low price might be exacerbated due to low liquidity and tax loss selling.

Here's one recovery analysis showing $0 for potential recovery of the bond. Though it should be noted that the author appears to have overlooked the Bitmain situation (as of Q3, Gree has $27M on deposit with Bitmain and a further $65M in mining rigs that have been ordered & paid for but not yet delivered).

However, even if Gree is able to monetize those amounts (big if), then they would likely spend that capital trying to hold out longer for a recovery in BTC. If that failed, then the Bitmain numbers may not materially affect the author's zero recovery conclusion.

Though buying time (by monetizing Bitmain rigs/deposit) might mean a few extra quarterly interest payments on the bond. All it takes is 2 quarterly interest payments ($0.53 each) to roughly cover the bond's recent price, so the risk/reward here is enticing if Gree is able to buy such time.

tl;dr - GREE & GREEL both have a high likelihood of ending up at $0. However, if Gree survives for 2 quarters & makes the next 2 bond payments, that would fully cover the cost of buying the bond today at ~$1. If Gree simply makes the January bond payment, then that covers 50% of the cost of the bond at this $1 level. At that point, GREEL could be thought of as a 50 cent call option - with a full breakeven if they make the June payment, and anything else being total profit if they survive thereafter.