Graduate Journals

The comments are fairly unanimous in response to this question on the merits of publishing in graduate journals - basically, 'don't do it'. Reading the comments, I ended up wondering why graduate journals are published in the first place - that's presumably a fair amount of time and effort going to waste if the comments are correct. It seems like there are at least some potential benefits to publishing in such a forum - peer feedback and experience of the publishing process are two that come to mind. Perhaps these journals would be appreciated slightly more if these aims were stated more clearly? If they are distinguished from 'proper' (I'd prefer 'professional') journals as serving different purposes then I'd hope people would not be held to account for articles published in such a way before their career had even begun.