Yes - I will never travel without them again. On a tour during my cruise in April, I boarded a speed boat in my bare feet. The deck was very slippery - I fell and hurt my back and broke 2 ribs. Was in terrible pain and could hardly walk for the remainder of the cruise. This could have been avoided if I had thought about bringing water shoes.
I wear sport type sandals that can go in and out of the water. They look nice enough to wear around the ship, except to dinner of course, but work well with those slippery water situations mentioned. I'm like you, I don't want to pack another pair of shoes when I have a multi-tasker that can do it all in one.