A few things about black ipa as a style (in support of why they are awesome):
1. The roast isn't nonexistent, it is subtle but present. It is like the sprinkle of cinnamon or cocoa on your cappuccino - it is a pleasant extra (if not strictly necessary) note.
2. They are easy to brew. By this I mean no worries about clarity. The wait time on an ipa can be painful because you want it clear, but you don't want to lose any hop character.
3. There is a lot of variety/unexplored territory in this style. Here in the bay area, few have even heard of the style. In Portland it is more common, but many brewers made theirs borderline imperial stouts and others made theirs dry as he'll and low in body (my preference). They range from the low end of abc/gravity for an ipa up into the iipa range. Some, like mine and the one at hop works, use just dehusked carafa or sinamar to darken it. Still others. Use chocolate malt and roasted barley to kick up the roast. True sometimes it steps on the feet of ris, but this flexibility is inherent inany "out of style" style, at it makes them fun to brew.
4. It is fun to be part of the bandwagon sometimes, and black ipa is the bandwagon style right now alongside sour beers. A few years ago everyone was enjoying wit biers with gusto, and a few years before that, people were first getting worked up over e word imperial. Sure it can be gimmicky, but it is sometimes fun to be in on the gimmick.