Why is reinforced concrete easier to seal? Why couldn't you apply the same sealant to wood? And why wouldn't you have the same issues, such as when you punch a

Why is reinforced concrete easier to seal? Why couldn't you apply the same sealant to wood? And why wouldn't you have the same issues, such as when you punch a hole in the exterior to mount something, or run wires, etc, you now have to make sure that sealant stays in good shape? Or expansion joints?