Ive never came across this sentence before. I was doing strengthen the course, cool.
I'm in a similar boat, never came across until I was doing the 'testing out to level 4' test.
No, כן is used here solely for emphasis reasons, like the 'do' in English. "Yes, I eat bread" = "כן, אני אוכל לחם".
Because of the כן. It works just like "do" in the English suggested translation, "I do eat bread", to express emphasis.