Good question. Frustrum culling is definitely implemented for 3D. You can test it. Make a 3D scene, move with camera, open the Debugger and open the Monitor tab. There is a number Objects Drawn. It shows 0 in 2D scenes and I think there should be something like Sprites Drawn for 2D (you could open a feature request on GitHub). But even though I can't test it, I'm pretty sure the sprites are also culled.
It looks like VisibilityEnabler affects only animations and physics. RigidBody is still simulated even outside of view. Frustrum culling is related to rendering.