I can probably highlight the two most interesting things that I do as a Local Guide:
Adding a foto. When traveling, you are in places that are poorly known to a wide circle of people, or the photos on the maps do not contain enough information about this place. You add your photos for such places, after a while you see that your photos are popular - people watch them. You feel joy from it - you helped people, you could make this beautiful place more popular, share this beauty with other people
Adding a new places. There are many places on our planet that are not yet mapped. By adding new places, I benefit society, making Maps a little more informative and useful to people.