I mean, in java this enchantment only increase damage to water mobs like, squids, fishes, dolphins, turtles, axolotles, glow squids, and the guardians (but not drowneds for some reason), making it very situational and a little useless. While in bedrock this enchantment increase damage to every mob (players include) that are in contact with water or rain, making it more versatile and usefull.
I know in one of the combat test this was changed to work like in bedrock, but these test were 6 years ago, and they were never added to the vanilla game.