Sounds like some famous people just discovered what a lot of people have been doing for generations.
I throw heavy whipping cream, coconut oil, half n half, and Kerrygold in my coffee based on whatever I feel like, but the grass-fed butter might be my favorite. Just a nice rich taste. I don't really see the whole mental supercharging that this guy is trying to use to make a buck, but it's a nice way to get some quality calories in and enjoy your joe. If I was a 120lb lady instead of a 220lb guy, not so sure I'd be eating so much of my days cals from just fat, but fortunately I have pretty high caloric demands so this is nice.