The water you see in video games plays a part in showing the overall quality of the graphics as well as the engine the game is running on.

You might think that all digital water is the same, but that is not the case. You see, in a cartoonish type game, you would most likely see the water look more cartoonish to match the vibe of the game. In some games, you may find that the water has a blue tent, opposed to being clear and reflective.

And then you have those games that being in the water triggers something like an enemy, instant death, etc.

At the end of the day though, most video games these days use water to make the game look good.