Power, Temperature and Noise
There's no need for a huge, overbearing cooler when the entire system consumes 162W at the wall. There have been times in the past where a high-end system would eat that much when idling in Windows Vista.
The single fan's characteristics have been tuned for near-silent operation. We infer this because EVGA could easily keep the temperature below 70°C if needs be.
Monstrous coolers are more for show than genuine use on a GTX 1060 GPU. EVGA shows that it can produce a well-clocked core, cooled by a small heatsink, that's practically inaudible under load.
The company strikes the best balance between a lack of noise and reasonable temperatures in an already-quiet PC.