Ya got me, I couldn't get it to work for me either.
I really wanted a frosty root beer and failed.
Smells a little like it but certainly doesn't taste like it.
I tried adding Bavarian Cream, Vanilla Swirl, Vanilla Cupcake, French Vanilla, and also Champagne. (individually then mixed some of those concoctions together)
I didn't have anything else that remotely made me think it would work so I gave up.