Yes. Let's pretend, for the sake of pretending that you or your child comes down with actual influenza, or strep, or COVID, or Noro or something that makes them actually SICK the day you want to leave for the trip. Or the day before. Every single penny you have paid for that trip is non-refundable.
Or let's pretend someone close to you has a heart attack/stroke/cancer diagnosis right before the trip and you need to cancel. Every single penny is non-refundable.
Or, let's say someone gets badly hurt while traveling. Evacuation costs a fortune. (I badly injured my back skiing. Over a thousand dollar ambulance bill and that was just to get me down the mountain.)
Or, let's pretend your flight is cancelled and you can't get a flight for two days and miss your cruise.
Your cruise is actually non-refundable fairly far in advance. Not just non-refundable, not re-bookable for credit. Money just gone. Maybe you can afford to wave good-bye to multiple thousands of dollars, but given that you are balking at insurance, I'm guessing not.