Why the ACES and Nuke configs only have a single display, mostly for
legacy reasons. There were tools which didn't work well with the
situation of having different lists of views for different displays,
so the ACES config structured all the views under a single display,
Ideally tools would be able to handle this case better.
e.g. if you have:
Display 1 with views A, B and C
Display 2 with views A, C, D
When the user selects Display 1 with View B all good, but selecting
Display 1 from a drop down which choice should be shown for the view,
the ACES config basically combined them to say
Display ACES, with views 1A, 1B, 1C, 2A, 2C, 2D
It is more in keeping with how OCIO is intended to be used, to use
multiple displays to represent different display devices.