Diversity in a story makes it more realistic.  If you look at our world, you will see people from all walks of life.  Backgrounds and experiences just as similar and different as the sun is to the moon.

Also, the depth of a character’s makeup can be a learning experience for the reader.  At the very least, a cause to research and evolve so that what is foreign is now familiar.

Photo: Sharon Drummond Before You Even Knew You Wanted Them via photopin (license)