What do you think of Facebook's Marketplace idea?

[Craft Boutique]

I saw an article today about Facebook creating a marketplace.
Is that a good news or bad news for sellers like us?
It's only offered as an app for now. But how many people use the app?
It also seems to be for used items mostly, so why they are saying it would create a serious competition for Amazon and Etsy? I am a bit confused about that point. 
So would you use Facebook's marketplace?