Oh, man, what a late reply, but I'll try to explain my reasoning behind the "redunant" moves.
I have both Surf and Hydro Pump because: I use Surf for fragile leads/other Pokes, like Gengar, Scolipede, Deoxys-S, etc. Hydro Pump is if I know Surf will not 2HKO, and I'm willing to let it miss...