Bottom line is, you're transitioning from VFR-to-IFR to deal with deteriorating weather conditions in the en route phase of the VFR-flight, with subsequent VFR-landing at the destination airport.
No, that's not the concept. You're
planning an
IFR flight, albeit with a VFR departure, so that it doesn't matter if the en route weather deteriorates because you have planned the flight without relying on being in VMC all the way along the route.
It is no different from an instrument rated pilot planning a flight between two VFR airfields. He must depart VFR and arrive VFR, but may choose to fly IFR for the enroute portion of the flight so that successful completion of the flight does not rely on VMC all the way along the route.