I have NO IDEA where that comes from!
I have heard the same thing more than once as well. I guess there are other methods around that take less time, but I am sure, will not produce the same finishing results you get.
What I have seen around, generally, is sanding up to 400-600 grits, deep etching and hand sanding to 800 grits. But it most makers don´t spend more time in this process than they spend in hand sanding from 400 up to 1200 grits to a really good satin finish.
Jeff Velasco