The other reason is pretty straightforward: people don't know much about traits and if no one is likely to use the module, I don't see much sense in adding to the terminology glut.

IMHO, people aren't going to learn much about traits unless they can use them in practical examples (at least, I sure won't, though I'm more of a "learn by doing" type of person). I'd like to see a useable version of traits so I can figure out how to best use the concept before Perl6 gets going.