LinkedIn's purpose is not to help you as a worker. It's purpose is to scrape together as much personal information about people as possible to make money from it.

Likewise Facebook doesn't exist to help connect people together to create a more personal, connected world. It exists to connect people so that they can get the users to share as much personal information as possible, so they can profit from that information.

It's always important to remember that on social media you are the product. You have to weigh what you benefits it is really providing vs. what you are giving up.