What is the effect of poaching fish in milk? I recently came across a recipe for fish poached in milk.  I've never heard of this technique, and am skeptical of its effect (vs. water), so it sounds wasteful to cook fish in 4 cups of milk only to discard the milk afterwards.

After a quick Google search, I found that it's done in some cuisines.  So I'm wondering what, if any, effect does poaching fish in milk have?
The milk sugars will add a sweetness to the dish. Also, after the fish comes out, the milk can be reduced/thickened to make a bechemel sauce.