https://docs.godotengine.org/en/latest/tutorials/physics/collision_shapes_2d.html#performance-caveats states that
When using a single non-transformed collision shape in a StaticBody, the engine's broad phase algorithm can discard inactive PhysicsBodies. The narrow phase will then only have to take into account the active bodies' shapes. If a StaticBody has many collision shapes, the broad phase will fail. The narrow phase, which is slower, must then perform a collision check against each shape.
From this it is fairly clear that what the problem is when you have multiple collision shapes. However, the wording of the first sentence seems to imply that there is also some kind of performance issue with single transformed collision shapes.
So my question is, what happens in terms of broad and narrow phase checks when I have a StaticBody with a single transformed collision shape? Will the performance be worse compared to transforming the StaticBody in the same way instead of the collision shape, and if so, why?