The Chalice is an attempt to include 'something like' the Long Serpent (aka Mercury) class, one of the more interesting, if rarely used ships in BFG (that tendency to explode is not a good thing sometimes).

I have no idea why they included the Armageddon. There are a couple ships like the Excorcist where you're losing more then you're gaining for a point or two of SP. What baffles me is there ar perfectly good ships in fluff that could have been used and made all the entries in the ships section unique and interesting, and they got ignored in favor of 'rename it and give it a mandatory weapon'.