I could understand 20% yield on HP. Or 30%. Maybe 50%. Probably sustainable, the Hive is obviously growing. And if the chain performance happens to fall behind, the price drops, we shrug shoulders and move on. No big deal.

I also understand those who prefer to hold HBD. I do not expect them to do it at 0% but 20% yield on the stablecoin just pushes them towards risky spot they wanted to avoid. There is no shrugging shoulders and moving on when a stablecoin depegs (and it should do so long before reaching haircut threshold).

The most obvious flaw in the logic that it is unsustainable is the implied assumption that this 20% yield is static and can't be changed. Witnesses can lower it to 0% if they wanted to in an instant. It's a dynamic variable that improves monetary elasticity and stability.

This literally explains you do not consider 20% sustainable. Even I can admit it is probably reasonable as a short term move but let's call it unsustainable if you do not expect it to last. It could be simultaneously unsustainable and correct.