He’s designed an incredibly simple brine hatchery composed of a base that’s 3D printed on the MakerBot, and a cut-off 2 liter bottle. This is significantly less expensive than a store-bought equivalent and you can make as many as you need.
These are simple objects, to be sure, but the point we want to make is that when one owns a 3D printer there are many such situations where even limited 3D design skills can produce very useful items. You don’t need to design intricate objects all the time; simple ones often do the job. They don’t even need to look pretty.