Jed,
I certainly look into it for my own purposes. There's always something that I don't know cropping up.
I interpreted the difference between those settings as being more to do with the part template that was used but nothing major about the part file that made the files distinctly different to the extent that they are only suited for specific uses. In other words you could delete the formats out of a file that you started by using a drawing template and simply start modeling in there because as far as I can see any part file can be used for a drawing, a model and assembly or even CAM. They all have the same file extension and can interact however the user choses. That isn't to say that it makes sense to do that.
Teamcenter is a different prospect because it can make use of the PSE to manipulate the contents of assemblies such that the ALTREP option can be used. All that means to NX is that it is loading a separate and completely different part in the assembly but that the part appears to be something like a different version of the same item, perhaps in an installed position, but not as a result of actually using the deformable parts feature of NX. It comes about because and item master can contain different datasets which is all to do with how Teamcenter manages or presents the management of your data, and very little to do with anything the NX seems to be doing above and beyond the norm.
Now if there was a reason for these setting and some functionality that I haven't encountered yet then I'm keen to get a handle on it. The above explains what I think that I knew and why I asked. The good thing about the forum is that we'll probably get some further posts to illuminate on the subject shortly.
Best Regards
Hudson