Tell me what doesn't compute - Swiss operating 9 rotations a day with either CS1 or A320 plus 18 trains a day from GVA to ZRH - thats a lotttttt a people on shuttling backwards and forwards and I bet they all don't live in GVA city!
Im not sure its rocket science to find 300 people a day from within the Valais that will see the convenience especially if then departing long haul via Swiss!