My DS11 has 2 severe gashes in his foot from not having water shoes on in the Typhoon lagoon wave pool on Sunday. I saw so many people walking out bleeding that it was getting scary. You need something that will protect all sides of your foot.
Blizzard beach is so stark white and blindingly hot on the pavement you can get burns on your feet.
Water shoes are horrible, uncomfortable, and yuckky in the real world but at the water parks they are needed!!!