Basically you can make or import a list of textures for a model so the user can save space by having one copy of the model that can have many textures to chose between instead of many copies were the only thing changed is the texture.
This would also make it easy to update the model since you would only need to update one model and all the textures would already use the updated model instead of vary slowly updating one at a time.
of course this is only useful for when there is many different textures for one model but it's nicer to just have the option.

It would be even better if this was supported by the ModelFile API.
I'm imagining code like the following:

// File file
ModelFile modelFile = ModelFile.load(file);

// File imageFile
modelFile.setTexture(/* texture_id etc */, imageFile);
// OR
ModelFile anotherModelFile = modelFile.withTexture(/* texture_id etc */, imageFile);