By February a dark pool colour in full sun can feel more like a bath than a swim. A pool chiller is a heat pump running in reverse. It pulls warmth out of the water so you can jump in after work instead of waiting until dusk.
Chillers make the most sense on north-facing blocks with little shade, or on darker interior colours that soak up heat. They are not essential for every backyard here. Plenty of pale pools stay comfortable with a cover, good circulation and a bit of afternoon shade from the house or a sail.
If you already have a heat pump, ask whether it can reverse. Many modern units heat and cool. We can spec that when we quote the equipment package so you are not buying twice. Bring your site photos to a consult and we will tell you honestly if a chiller is worth it on your block.