FESS Fesshole HOLE @fesshole
We had a cappuccino machine, I thought my wife kept cleaning the crispy dried milk off the steamer spout, she thought I was doing it. A year later, after coffee every morning, we found out the cat was licking it off when we were at work.
It doesn't disinfect the exterior of the nozzle and that part ends up in the milk that's being foamed.
A damp cloth won’t do that either
But it prevents build up, which feeds and encourages bacterial growth. With bacteria is never about total absence, but numbers. The body can deal with a few hundred bacterium. But if instead they're several hundred million. That's when you start having risk of disease.
So does the cat.
The logical inverse, if wiping it off does nothing like you say, would to be then rub a cat turd on the nozzle and it should be fine, since it's not like wiping it off helps.