I've been on this train. The sound of the train being pulled onto the ferry did wake me up to say the least. It was dark outside and the blinds were shut in our sleeping coach. I remember feeling a bit of a weight, being in bed, in a closed coach, inside a large train, deep inside this massive ferry with many floors above us. It wasn't until much later that I realized that the train was open-air and not that big at all. You then wake up a few hours later near Palermo where the train runs just by the ocean – that was lovely.
I've also been on the second-to-last train of this type a few times (Snälltåget from Sweden via Denmark to Germany). That one also got canceled for the same reason – mega bridge construction (Fehmarn Belt). There, you used to get off the train to go up to the canteen for lunch with the truckers.