In regards to benefits of having a quiet disposition? I'm good with kids as well as animals.
The reason why listening from being quiet helps in customer service is that I can tap into what the customer is asking/saying and let them feel heard etc.
And if you're looking at factory work, most jobs one needs to keep the hands busy and truly though many people can walk and chew gum-being an adept conversationalist seems a bit moot on a factory line.

If that were to come up again in an interview, ask them what they mean by quiet? Is it something else?