Not sure either....I mean, I've read about the butter "beer" they make at Hogwarts universal studios, and how people have tried to replicate it, with some success to varying degrees.....Most times a lot goes in AFTER the beer is done, making it a wierd root beer float type thing... (real butter beer from the 1500's actually uses a stick of butter mixed in the ale, but I digress)
However, this, with the adjuncts, looks like it's make a great base, and a potentially sweeter/flavorful beer beforehand, so I may give it a shot.