There is no reason why the inverted mesh method shouldn't look good
Well, it will look okay, most of the time. . . but:
1) there's the problem of consistency in the thickness / visibility of the lines (something far away will have lines that are really thin and disappearing)
2) you can't decide exactly where you want to draw the lines, even though most of the time they appear in the right place. But what if you wanted to always outline certain edges, and not others?
3) There's the problem getting nice smooth lines, that are antialiased. . . (You can do this with line drawing, although it would take a lot of processing time)
I do admit, that if I'm going to be working in a real time game with lots of cel shading going on, I'll probably use the flip mesh. But I still want to experiment with other ways and see what kind of cool alternative effects I can create for quickly rendering a video sequence.
I think that line drawing will prove to be a much more flexible and artistically useful technique, even if it's too slow for real time. It's still going to be hundreds of times faster than doing full-blown edge detections on the whole screen! :O)