Each have their place, but steemit has an actual place for entrepreneurs and people who create great content to be financially rewarded. Facebook is great for sharing photos with friends and family and posting about what you are up to, but you rarely gain knowledge from Facebook unless you are following news posts. There is no direct messaging system for users here, but being able to be rewarded for thoughtful comments encourages people to think before they post if they are serious about the platform. And Facebook changed a lot from its roots as a means to stay in touch with college friends to being open to kids and adding apps and games instead of simply having a wall. Steemit also doesn't suffer from intrusive ads and will continue to evolve as more users flock to it. I'd much rather browse steemit for content and Facebook for friends photos.