Chances are you haven’t seen a metal key for a hotel room or cabin on a ship in a while or ever.
Typically you get a plastic card that you push into a slot.
But even that has evolved to cards that you simply hold up to the door, or a bracelet or charm that does the same thing.
You will see more and more advanced technology. For example, according to Travel Mole, Holland America Cruise lines is installing a facial recognition system for checking in to your cruise.
Overall you will see less paper and more apps and technology as you explore the world.