The benefit of using prims is that you don't have to reinvent the wheel every time, which is most true for big chunks of parts. The forced use of boxes might be questionable, rects - especially when they are rotated and rounding errors start kicking in even more - but the use of rounded prims is unbeatable. This is most true for prim substitution in viewers such as LDView.
First time I used modern CAD tools such as Solidwork I learned it the hard way how important Marc Klein's modelisation tips are and that a possible substitution of code with prims has to be planed in advanced:
http://marc.klein.free.fr/lego/parts/modelise.html
when converting a STL to the low-res LDraw ecosystem:
http://marc.klein.free.fr/lego/stl2dat/stl2dat.html
w.
First time I used modern CAD tools such as Solidwork I learned it the hard way how important Marc Klein's modelisation tips are and that a possible substitution of code with prims has to be planed in advanced:
http://marc.klein.free.fr/lego/parts/modelise.html
when converting a STL to the low-res LDraw ecosystem:
http://marc.klein.free.fr/lego/stl2dat/stl2dat.html
w.
LEGO ergo sum