I use this as well in Studio One Pro 7. The reason is I sometimes use backing tracks I put on my Ipad and I keep my volume consistent between songs. Also this is the standard anymore for streaming music. I have no reason to use another program to set my volume.
Brian, you and I have similar philosophy. For the reasons I say above, I don't want more than one DAW in my workflow.
This way, if I (or someone else) doesn't like the way my mix sounds there's only one place to look to solve the problem . . . Studio One.
My engineering brain has always served me well when it tells me, "minimize the variables wherever possible".
But other's mileage may vary, which is all fine.