Segmentation of the view is useful to avoid to load too many items not only improving performance but also the human ability to seek within a large list. I don't think the artist sidebar needs to be segmented though, even considering the fact the pattern for segmentation isn't really ironed out and there's probably better means to do it than a button at the bottom. It's sorted by name and only features text labels making it unlikely to be slow and generally fast to seek in.