@jsstaedtler I'm a very casual creator, but I have thought about this.

I'd like to let other CC creators to use part of my work (e.g.a paragraph) in their works.
But Share-Alike can make this difficult - if my paragraph is licensed as SA then the other author's work must be as well - which poses a big problem for living creations (e.g.a book being written one chapter at a time) where the license might have been decided on years ago.

(But this isn't a problem I've seen, just thought about)