Here are three things about various attributes that can be found in Creative Commons licences, which I find are not necessarily obvious, but good to know (details on the CC site).
First, when a CC licence has a NonCommercial (NC) designation, it means, roughly, that employing the work for a commercial use is not permitted. But it’s not quite that straightforward. The work’s creator wants other people to use the work (according to whatever permissions they’ve granted) but does not intend anyone acquiring the work through its Creative Commons licensed version, to profit from it.
There’s an interesting distinction though between use and user. You can’t make a blanket assumption about the use of the work based on the person or organization using it. Even a for-profit company for example, could use an NC designated work for a variety of things so long as they’re not selling it for profit (which would then qualify as commercial use).
The ShareAlike (SA) designation results in something like a viral impact. When someone licences a work with SA then other people that for example make something new with it, also have to release their new work with an SA designation in kind. This is beneficial in that those adopting it, potentially increase the availability of new works and ensure that work continues to be shared (nourishing the commons). This is akin to the requirements in Free software licences like the GPL, which have contributed to an extremely large Free and open source software ecosystem.
And finally, if the NoDerivatives (ND) aspect is present in a CC licence, it’s actually more permissive than it might sound. It does not prohibit making derivatives entirely. The Creative Commons pus a lot of emphasis on the commons, an effort in large part to increase what we can all share access to. So in that sense, ND has more to do with the act of sharing a derivative than of making it. That’s to say, you can make a derivative work of an ND-licensed work but you don’t have the permission to distribute that derivative.
Copyright gives the people that create various works, certain legal controls over those works. As the name suggests, it limits copying (thus various forms of usage) to those authorized to do so. Depending on jurisdictions, it also codifies things such as moral rights.
The Creative Commons licences simplify an author’s ability to authorize copying and use of their work. CC licences leverage the control that copyright establishes and an author can use these licences to, in a sense, automate control. Rather than negotiate requests from every party that wants to use, derive new works, or copy the work, an author can clearly state what they’d like to be able to happen with the work upon expressing it to the public. Then anyone can use it as the author has intended.
Because the CC licenses are not just written with legal use in mind but also for a layperson or machine, it’s relatively easy for creators to take advantage of these licences without entering into a more complicated process.