Well it's nice to see that you have beaten me to the question.
I was just looking through the forms to see where to post this exact question.
I am a Med Card holder and live in a state that has a 5 plant count maximum.
(clones under 5 inches do not count towards your number of plants)
The big advantage I can see to this method is that it would allow you to have a much larger clone, and it would still not count against your plant count because it is attached to the mother plant still.
I have just recently learned of this method, and will give it a whirl on my next to plants coming up in Veg.
It will be a bit, but when I give it a try I will update in my journal (WillieP's World) and here as well.