If I remember correctly in the video linked says that the coffee is at the “right drinking temperature”. I don’t know about you, but I drink my coffee 10 seconds after pouring. Presumably if the coffee is in contact with a frozen surface, it will be significantly cooler than what I’d classify as “right drinking temperature”.
DFK - Do you often leave your espresso to cool down prior to drinking? Do you warm up cups at all? Some say that one can pick up more flavours/tasting notes once the beverage cools down. I think that’s true, but I’m not a fan of drinking espresso lukewarm or cold. How about you?