Because I saw it worked on the video uploaded yesterday. Check the screenshot attached. I’m not sure that’s the same program since the author published 2013, but I can clearly see who made that program, exactly the same name texted on the application, and video that used that application and hacked iap was uploaded yesterday. Means that some guy used Billing Hack Application in 2020.
From the screenshot, the author & programmer is Dominik Dschuermann which is exactly the same name so I can guess the same developer made some kind of “improved version” and it still works in 2020.
The video I saw a man used that program uploaded that yesterday, he used it in my game.