The contact wires aren't exposed on the wall plug, they're protected inside the outlet

The plug that you're putting in isn't supposed to be energized until its mostly inserted and difficult to touch so the fact that its exposed metal normally is fine. Basically the reason male-male AC plugs are bad is because the violate the rule of keeping energized surfaces out of reach

Small interior pins that lay on pads struggle to carry any significant amount of current without overheating. For anything that you need to pump >8A through you really want a very firm connection which is generally a pin or equivalent with springy metal bits pushing on it from each side to ensure good contact

We do this with wall plugs, the prong slides between two bits of springy metal that ensure contact. High power test equipment uses similar pins that slide into spring contacts.