This will be very good for Facebook having to tokenise their space. Facebook has improved over time especially the aspect of adding reward for posts. With a digital asset it will be easy to have a global outreach.
The only advantage this Facebook coin will bring is global adoption of cryptocurrency and am happy to see them raising fund for their coin. According to OP, Facebook coin will be decentralize and may be able to measure up with Bitcoin. Bitcoin be the mainstream of the blockchain will still be operating as the king of cryptocurrency because of it dominance.