After the data breach of Facebook, Now facebook introduce more features to catching people’s attention. In this way, Facebook now introduced Nearby Option in their Facebook.
This option in Similarly in the Snapchat Nearby option. You could ask that Facebook copy Snapchat in the Nearby feature.
with the Help of this feature, you will know about your nearest friends and meet them. But if you don’t want to meet them and if you wish that No one see you that where are you now. So you can turn off this option.