It is not so easy to use it. I did. If you don't call the functions in a specific order (at least for reading a MDL7) it crashes. But if you do, you can easily transfer the model data into your own datastructues, which might be better engineered than the SDK' ones.

Saving a model in the engine with the SDK includes much more than just calling some functions in the SDK, though. If someone shows, how to e.g. read out which triangles connect which vertices and how one could access the UV coordinates (I, for instance, don't know that), one could write a very basic function that translates that into suitable datastructures for the SDK and then you can save it.