Facebook is trying to make it so you never have to actually leave the app - even if you want to order food. The feature is run through partners Delivery.com and Slice. All you have to do is go to the Explore feature and click on the hamburger icon that says “Order Food.”
From there, you see a selection of the places that will deliver to you in the area - much like Seamless or Grubhub. So do we really need this feature if we have other apps that do the same thing? Who knows? It’s easy for people who are on Facebook often and don’t need to be bothered with a bunch of different apps.
Maybe it can even reach a new crowd of folks who don’t know about the wonderful world of online ordering!