>>45115911I think it's a bit of both. I 100% agree that Seafoam Island was the intended route, but I think Gamefreaks was also aware of the easier pallet town route.
The thing is, the only practical way of even reaching Pallet Town that late into the game is via Fly, which is semi-hidden near Celadon City. So they probably figured if you as a 7-year-old kid were smart enough to find that move and put the pieces together like that, they could throw you a bone and let you get away with skipping the cave.
Unless you were backtracking via the Diglett Cave, in which case you deserve this bonus just for your sheer level of determination.