Maybe I just too traditional, but there are far more mature back end frameworks available, without the warts of JS. For me I prefer to see a need or justification of using the latest software trends, not just because "its modern" or "that's how we do things nowadays" (a genuine response to a project I am involved in when I asked the case for using Node).
Node.js obviously has some use cases where it will shine, but I wouldn't have thought a BB was one of these places, as its quite a traditional kind of app.