> (Also technically no CC licence is an open source licence, since they don't require works to release the source code, because they aren't intended for source code)

The MIT and BSD licenses also do not necessarily require the release of source code. It is just that if you license code under those terms and pass it to someone else, then they receive the rights to do a lot of things with the code, including releasing it. I don't think that is much different with the CC licenses (the non-commercial variant is definitely not open source though).