I have Deck drains that drain out to the street.. You don't want rain water to run into your pool.. In my case, there is no place for the deck water to go.. Without deck drains the only place water could go is into the pool and then into the house..
They work great for me. The main downside is that the deck has to be slopped toward the drains.. It is not much, and you don't notice it until you try to put a chair or a ladder in the wrong place.. I'd do it again in a heartbeat.
The contractor says they work great but just wanted to check with others. On other areas of the pool he said we can use the drains or let the water run off down the sides of the retaining walls. The only reason I can think of running down the retaining wall is algae growth. So, I'm debating on that portion.
We are using them in our build, but unlike Jim, ours drain to the back of our yard, via pop-ups. (This is how our yard naturally drained, before the pool build). Our old house pool drained out to the street, like Jim’s.
I can drain out the back because it's all down hill. But on the back side will be a pool house and don't want the water running towards it. Then on the front side and house side, there will be retention walls with no where for the water to go. Then on another side, it will be open decking and could run off the deck and down the retaining wall.