We occasionally book a JS. It depends on the itinerary, ship and price. We booked this one for the unique set up with the solo cabin and JS with the small-internal hallway and the large balcony. We have not sailed this class of ship--but, it seems like a small apartment. So, eating in CK did not enter into the reasoning for booking a JS.
But, I am curious. Since JS are allowed in CK on a space available basis for dinner, is there a reason you did not even check into it. . . . I wondered if you felt it was not a great experience when you tried it.