I don't know, as someone who has neither, I would think that potentially losing your sight or hearing is pretty serious. Not as serious as other life threatening things that can happen with WG, but that's huge.
That's just it-- they have it in the category with life-threatening things like alveolar hemorrhage, stroke, kidney failure, etc....
I guess that I look at it like paralysis -- not immediately (or necessarily ever, I suppose) life threatening but a serious and permanent life altering event. I would put stenosis in that category (don't know if BVAS does or not), and it's not immediately, only eventually, life threatening, and sometimes not even then.