What was the point of the Nightmare Critters?

I'm not going to bring up Pianosaur as we ALL can agree they did him SO dirty! But the Nightmare Critters were pointless too! Say what you want about the Smiling Critters, but they kinda did something and where important to the plot. Obviously cuz of Catnap and Dogday, but they had a presents though out the chapter. What does the Nightmare Critters do? I thought they were pointless from the beginning as we didn't really need edgy Critters but fine. But even in their debut chapter, they were still outshined by the Smiling Critters! All they were used for was mod swarm, having to be shot at by the flare gun just like the Smiling Critters, and you had that one boss fight with the sheep that was more annoying than scary. Why introduce these types of characters if you aren't going to do anything with them? They don't even talk or have their own talking billboards! Pianosaur was at least thought of for more than a second for that! They are so forgettable! They should have just stuck with the Smiling Critters and not make new Critters! Like I know it's for expanding the world building as companies in real life do do this but why not do like they didn't chapter one with the other toys and just show that they existed without them doing anything! So dumb.