Hey urumomo, don't knock it till you try it. Here's how I happened upon it. I needed some rushing water for a small diorama I was making oh 30 some odd years ago. And as grandiose plans go I was going to make it as real as possible all 3D like and all. In other words attempting something wayyy beyond my skill set at the time. So I built the trestle and proceeded with the stream bed. I used a latex rock mold I had created and cast some plaster into it. While the plaster was still soft I pressed it in place as the river bed, once the plaster had set I pealed off the mold to discover the casting looked a heck of allot like rushing water. So I grabbed my oils (my paint of choice) for rocks and after some final dabs of titanium white for the frothy white caps I had an amazing fast water effect.
I totally understand your scepticsicsm but try it you may like the results depending how it's used.