asharrow,
Just further proof that there's thousands of ways of doing anything.
Did you ever have a college professor send you home to write the directions to making a peanut butter sandwich? Very interesting results, and one of those results is that it is entirely possible to have an infinite variety of ways of doing anything, and yet still arrive at the same finished result.
I've done it the way that you've mentioned as well, but I really didn't notice any difference in the smoothness of cut. This jig works for me because my router is micro-adjust for vertical adjustments. It's super easy for me to keep the jig secure and move the tooling. But, depending on your router, you may want to keep the tooling secure and move the jig, it's up to you and your tooling.
(That jig and fixture design course that I took in college finally paid off!)