Hi, thought I'd respond to this because its something I have a lot of experience with. I got into miniatures painting recently, but I've been doing ink sketches via stippling for a very long time.
From a sketching/drawing perspective, stippling is the most effective way to control the value (miniatures people call it shadows/highlights). Stippling is meant to make whatever it is you're drawing look like It's impacted or engraved, but on a miniature its mostly used just to shade colors. If you've ever read the wall street journal, there are stipple pictures at the bottom of every front page.
Here's an example of how stippling used in drawings should be applied to miniatures. I got back into the hobby after seeing this because its really a work of art, not just a cool mini.
http://boardgamesminisandmore.blogspot.com/2012/12/warmachine-lady-ayana-master-painted.html?m=1
Pay special attention to how the stippling is used to create a pattern. Really can't say how in love I am with this mini because it uses the very same technique I use when doing pen work.