It gets little use in the sense that only a small fraction of vulnerabilities are reported there, and there are very few non-advisory discussions (often by the same 2-3 people).
It does get use in the sense that every now and then, some vendor sends 50 emails that could've been one (most recently, some Apache Qpid thing). But I wouldn't call that part valuable.
So where's the residue of vulnerabilities that don't get sent there? You know of anything better?