Well in some respects it is redundant, pretty much all of the words in the Oxford dictionaries are also in the ABC/NWP, but the Oxford ones can sometimes be a bit more detailed, and in trying to understand the meaning of a new Chinese word it's often very helpful to have more than one dictionary's take on it. (which is part of the reason we're now preparing a Chinese-to-Chinese dictionary for release with a future version of PlecoDict; again, it won't add many words that aren't covered by our existing dictionary, but it'll provide a lot of extra information about words that you wouldn't get from the dictionaries we have now)