I've always used them to connect good roads together. Just riding through the neighborhood in the most direct way possible. Over the winter I found out about a game that gives points for riding every road inside the perimeter of Atlanta.
allofitp.xyz
Since then I've been picking a subdivision and riding all the roads in that specific subdivision. It's quite fun, it gives a real sense of the area and the people that live there that just doesn't occur when riding straight through. As you ride along and spend time in the subdivision people come home from work or are just walking around. The sun starts setting and lights come on as dinners are prepared. It's homey and relaxing and gvies a different view of the world than cruising down the road with cars.