It's not what I would consider to be roasty and doesn't taste like an IPA dyed black with flavorless sinimar. The dark malts it uses contribute flavor. Roasty to me is more coffee like. Sharper. More astringent. There is no universally accepted definition of Black IPA as far as I know, but minimal roast, smooth dark malt flavor and C-hoppy is what distinguishes it from a stout or a porter, in my opinion. Wookey Jack defines the style for me.
They say big and roasty, but that is more marketing than reality. Roasty sells beer!