Mike Linksvayer commented that the Share-Alike license, which requires a downloader or remixer to themself allow redistribution and remixing, allows inclusion of a SA work into a collective work which is not as a whole also under a Share-Alike license. For example, my releases on this blog could be incorporated into commercial CDs and forbid redistribution or remixing of the CD as a whole. This is important because the requirement that reusers are bound by the same commitment as the original creator is the main defensive feature of this license.
And gurdonark had this to say about the Share-Alike license:
While most CC licenses seem to me relatively straightforward and issue-free, the [Share-Alike] designation and its accompanying license gives me the most pause about whether it will require a court to interpret how its intricacies work.
I agree with gurdonark that there is a lot of complexity lurking under the surface of the SA license, but I feel confident that it strikes the best balance between promoting my creations and defending me from exploitation. So what if my track on a compilation CD is the only one under the same license? This helps me and hurts the others; I profit at their expense by using this license.