I think Apple needs to come up with a better indication — perhaps something more explicit, the first time you encounter it — that you need to click the hardware button, not tap something on screen.
I have to agree, I did not “get” how to purchase apps to start with (one of the first things I did with my iPhone X), once I knew how to do it then it was obvious – so I would guess the physical action came first and the animation later, when everyone testing it knew how to use it.