I would not call it an enterprise security solution. It is also very much aimed at the ordinary user's machine. It is important for DRM (the infamous TPM chip is now basically an app running inside the IME/PSP). Decryption of DRM content takes place inside the IME and it is presented using a protected media path. So the content industry wants to have that on your computer. Intel also tries to market it by offering security solutions like 'Intel Anti Theft Technology' or its 'True Key' App which utilizes the IME. It makes your machine uniquely identifiable and it should serve as a store for all your secrets (like biometrics, passwords etc). Intel is also opening the IME up for third parties to create software for it. So your bank might e.g. run it's software inside the (considered safe and secure) IME. But of course such software has to be signed by Intel before.
Ruan even hints in his book at the possibility that one day the IME might become just as powerful as the user system. So it would be possible to run e.g. a game completely inside the IME, absolutely safe from the malicious user who might try to copy it. All you get is the output on the screen and the speakers. So the (considered unsafe) ordinary user space would just remain for running and storing trivial tasks and information. Everything else runs hidden away from you.
And all of this is supposedly for your own good and security. I would call it a dual use technology which (dis)owns the user.