I have gotten the insurance on my last 2 trips. I had to use it the first trip I purchased it. I didn't need it on my most recent trip though.
My DD who was 19 months old at the time, woke up with severe vommiting the morning we were supposed to fly home. I had to go to the ambulatory care center and the MD told us she couldn't fly. She had a urinary tract infection and by the time we got to the clinic was getting dehydrated. Later on, we had to go to the hospital in Celebration to get her rehydrated with IV fluid. We had to stay 2 extra nights. The insurance reimbursed my for the extra hotel days and reimbursed all our meals. Also, it covered the entertainment expense for DH to take DS (8) to DQ on our "extra" day there. The agent I spoke with on the phone was a very nice gal who helped me cancel my airline reservations, and book the new ones. The insurace even covered the $75 per person fee we were charged for changing our airline tickets. I had a letter from the doctor, and had to keep all our receipts. The form was kins of a pain to fill out, but the check we got back was well over what we had paid for the insurance in the first place.
I have been to WDW over 30 times, and this was the first time I actually wanted to leave.