:) One reason I can think of is that Nature isn't "symmetrical". Even leaves aren't quite symmetrical, and what we get in 3D is a lot of symmetry. That makes for a too "tidy" looking nature. And that's one thing nature isn't. Also; I've worked a lot with plants in different 3D apps. And it seems difficult to get the right amount of transparency and bump. Most leaves are a bit transparent, - and the different transparencies on the different species are different. I think that's part of what makes photography out there so interesting.. the play with the lights and shadows.. ..just my early morning rambles with too little coffee...