I don't see it that way. Most of a DE's output is actually reflected and by that effect diffused.
LED light is mostly unidirectional with no diffusion other than atmospheric refraction. Any leaf not under the sweet spot, or any leaf shaded - gets bubkus.
and let's not even get into penetration... (lol)
You sure about that? This is the light spread of a typical white LED (cree 5630) with no diffusor, just the LED itself. So at a 45 degree angle to the light you get 70% of the lumens you have directly underneath it.