Hori's Play Stand + Stylus is a well-built stand for your DSi, I'm just not sure what the point is.
The stand holds your DSi horizontally or vertically and can be adjusted to whatever viewing angle best suits you, but besides using it with maybe the Nintendo Cooking Guide, I don't see getting a lot of use out of it.
It is a nice way to display the DSi when you're not using it, I suppose, and for $15 it's not too pricey. Am I missing something?