We should break pools out into two different categories - indoor and outdoor swimming pools.
Indoor swimming pools are generally more accepting of different materials because you don't have problems with ultraviolet light, debris, and generally have a temperature controlled environment. Here a strip drain or deck drain will effectively do the job. If you choose such a drain consider one with a removable top because if you can't get in them to clean out debris even indoor applications will see enough sand and sediment to plug this small profile. For commercial applications it is still recommended that a larger 4" I.D. drain be used.
Outdoor pools should be 4" I.D. The debris will plug any system smaller than this in very short notice. Choose 4" outlet piping as well so that the system will pass any debris that gets into the trench drain. Any outdoor trench drain should have a removable top for cleaning of debris. Outdoor trench drains should also be UV resistant. Be careful of colors and materials that can heat up. The sun can make many dark colored or metal drain tops too hot to walk on.
Drain tops should be slip resistant and toe proof. Look for grates that have small openings that kid's toes will not get into. Grates with a nonskid surface are preferred.