In the DMI Editor, there is an import tool that is not exposed to users directly/alone. If you want to use it, you have to open the GUI and click several times. Having it exposed to the user, saves users some time and allows them to do cool things, like make their own additional tooling.

* Atomix graciously provided a nice use case.
The use is just automating importing large amounts of assets at once. Let's say for example, he has a bunch of gifs that will represent their own dmi. Instead of having to open the dmi editor, click import, then click the gif. He can easily make a script called gif2dmi, and just have it read each gif. I recall a user making a workflow as followed: Take individual icon frames. Stitch them into gifs, then have to open up the editor import. By making this available via command line, you also enable users to do things as simple as provide rules for where a gif is supposed to go so you don't have to open multiple icon files.

* how I can use this for tooling:
If I want to apply effects to the gif, like a dynamic hue-shift, I could chain the processes using a scripting language of my choice. For example, I could run a script that applies the dynamic hue-shift to GIF and then invoke gif2dmi directly resulting in a dmi, which saves me a tedious steps and makes me happy.