I have to disagree. I have spent quite a bit of time researching MMI's, and watching examples of it online. Generally, what I gathered from each example I saw is that the entire 5-8 minutes was a sales pitch, but not in a good way.
Take the example, "What would you do if you had a gym membership and your friend wanted to use it." Obviously, it is unethical, and it is not fair to people who are actually paying. This friend is placing an unnecessary burden on all of the users of the facility because she isn't paying into the system. In addition, there are other alternatives. Why not tell the friend that I will cancel my own gym membership, and instead just go running or biking with the friend outside. So given that there are a plethora of alternative options, and the fact that it isn't fair to the facility or its users, I would not allow them to use the facility.
Guess what, that answer took 45 seconds at the the most, and I just failed the MMI. My answer was clear, concise, and to the point. Unfortunately, I didn't spend 6 minutes repeating myself using different words and synonyms. I didn't sell it, I did it wrong. I needed to go on detailing possible situations such as, is my friend obese? Can they even afford the gym membership? Etc. etc.
So in essence, I disagree with the MMI because they don't truly evaluate the person on a deeper level. You don't get to see if they are genuine or kind. The only thing you get to see is if the person can ramble for 6 minutes and repeat themselves.