For some reason in the back of my head, I remembered that Silph Co trainers are hilariously underleveled if you've gone through all the side routes and done the Koga gym, so I thought of doing it the way you did--but chose to go to fuchsia first because of the Pokemon Go integration.
Speaking of PoGO, all I need is two Omanyte/Kabuto to finish that dastardly research series lol