All of my music is already stored in the cloud with my personal OneDrive account. Why do I need to re-upload everything to "your cloud" in order to use the app? Why can't GradedBlue simply play music from an existing cloud folder?

Besides the time and effort it takes to re-upload hundreds of music files from my cloud to "your cloud", now my music is in two places which means extra effort to keep them in sync when I decide to add or remove songs from my collection.