By requires, I mean; "extremely fine lines or extremely fine details, like fine lines.
For the most part, you don't get that detailed on a lexan body. Search for "painted body" on Ebay. I'd wager 95% of those killer bodies you see were done with masks and basic airbrush techniques and very little "freehand" work. Like the outline of flames, thats done with masking, so the airbrush itself has very little to do with the outcome. This is not to say that because a mask is used, its not complex, or easy to do.
So, what do I use my Iwata for: Well things like this where subtle shading is required for skin tones (probably don't show up real well and which a VL could be used for. But also face details...)
When I get right down to it or to the point, after you have a "quality" dual-action internal mix airbrush, it comes to "artist" ability.
No matter what airbrush you wind up with, an Iwata or any other expensive airbrush won't make you (third person you) a better painter. That comes with practice and possibly art classes to understand "colors"