@Roshuno the manga is complete, the light novel is still in production though. The only thing we're waiting on is potential extras from the published version of volume 2.
@Nirimetus Well, who decided it or why it was cut short doesn't really matter to me as a reader. A manga that ends so abruptly and obviously unfinished is jarring enough to get called axed. Even the fact that the novel keeps going is nothing special at all - it's been that way with both anime and manga for decades.
So long as you go in knowing that this is just an advertisement covering a single story arc, it's fine and quite good fun. Doesn't end on any sort of terrible cliffhanger either (though one or two bits of important stuff aren't resolved, of course).