It would most likely be used as a summary or a decision or a pointing out of an fact that is being overlooked.
Some examples might be:-
"I'd like to go to the cinema but I have to do some work, and I want to see something on TV and I have to wash my hair...."
"What you really mean is that when it really comes down to it, you don't want to go"
"I like to learn languages by listening to the radio, reading books and watching films, but when it really comes down to it you have to speak to people"