Hudson,
Many NC programmers still use 2d curved for most toolpath boundary type geometry. I know it's been beat into our heads to use sketcher for everything but... quick and dirty works. I expect in the not too distant future though, explicit 2d curves will be a thing of the past. Heck it's just this year I've decided to stick with the newer hole creation (position sketch based) rather than the Pre-NX5 hole function. : )
--
Bill