If no equity is used, then with respect to equity you cant calculate a return. You could call it infinite if you like. Or you could invest one dollar of equity and have an IRR of a bazillion % on equity. But is is also higher risk as you said. To be fair there are also costs associated with all the efforts required to execute etc, which was mentioned above.

I just don't see that much disagreement on the issues really. Just talking past each other.