For all of you sump masters out there...

Why the overflow box? I'm thinking that the water goes into the overflow, then over and into say a 1" pipe. Why not just have the tank water go directly into a 1" pipe that is extended up to near the surface? You could use gray PVC and it wouldn't show too much.

Just guessing, but possible reasons for the overflow box:
1) Less noise, especially if your surface is turbulent
2) Easier maintenance -- you could easily dismantle your drain pipe with an overflow box present. You would need a shut off valve below the tank to do drain pipe maintenance if you did not have an overflow.
3) The overflow box is a good place to bring in the return from the sump and keep everything together.
4) The overflow box is a possible catch basin for any critters that go over the top of it.
5) Aesthetics perhaps...

Just curious...