That's funny how people can have two totally different opinions of something collectible. The neater and tighter the better for me. I think I also like the fact that it takes more skill to do one in pen because there's no margin for error. With pencil they can just erase and redo the mistake.
Keep in mind that oftentimes, with an inked illustration, the pencils were put down first. Then inked over the top. After that, you can erase the pencils, and leave the ink intact.
But certainly, if you're only working from ink, there isn't a lot of margin for error.