Why does the dub bother keeping any music from the Japanese version at all?

Wait wait wait - I think I'm misunderstanding some points. They're replacing music to save money? Wouldn't it be so much less work (and less money spent) if they just left all the background music as it is and just simply dubbed the voices of the characters?

Well, they have to pay money to license the music, but I'm not sure if that's more expensive than producing their own (I'm leaning towards inexpensive, if the point about original voices > dubbed voices in terms of affordability is viable as a comparison). Either way, both scenarios make no sense.

Japanese music is more expensive - Why not replaced the whole score?

Japanese music is cheaper - Why not use the whole track?

Either scenario, they're just changing the original work for the sake of changing it.

Plus, I haven't touched much of the Pocket Monsters dubs since the early 4Kids ones, but in terms of those, I remember that they sometimes replaced pieces of music only to use the very music they replaced in a different scene - meaning they already owned the rights to them but choose to compose their own music for the hell of it. Huh.

Certain dubbing companies make no sense to me sometimes. As Lord_Mewtwo kindly pointed out, the Brazilian Portuguese dub of Digimon apparently had rights to the Japanese music and the English dub opening theme... why not one or the other? Man, I'm glad most English localization companies have a more sensible rationale nowadays.