I actually never have a syllabus couple start with a 1-3 of a Natural Turn as they can’t get the flight and therefore the swing on the Natural Turn that is needed to do it nice. Again that is my opinion and I totally accept that others don’t agree with me.
From what I've seen, in American style syllabus, nearly every routine that begins in closed frame begins with a reverse turn. Maybe that's why.
We start our standard waltz with a natural spin turn (so after the prep step we get 1-3 of a natural turn). Now obviously I dance pro-am, but the local guys who also do pro-am with their teachers, also seem to start with it. Maybe it's a local thing. My american waltz does not start with a reverse turn, however.
We talked about this in my lesson the other day and basically that beginning natural is usually our best natural in the entire dance. We start off with a prep, we are well-connected, it has what it needs to look good. I saw that in my videos. However, when it happens somewhere halfway in the song, it is not as good. Usually because something of the initial connection is lost and so it just does not have the initial quality.