Waze is great for commutes or other local driving you don't normally need nav for because the traffic routing is top notch (I've had experiences where it has told me to exit highway immediately and easily saved me an hour because of a terrible wreck that just happened). Also great for identifying speed traps on the highway which is why it's really popular with truckers.

It has international appeal as well, the map editing feature has made it a hit in places with less than perfect map data:

https://www.washingtonpost.com/news/innovations/wp/2014/10/2...