It's interesting seeing Facebook taking on YouTube. It's always good to have more competition but it feels like Facebook is a different experience and will make it much harder to "watch real videos".
Right now Facebook is stream oriented and we do watch some short videos while scrolling but that will never turn into the kind of engagement that incentivizes ads. They will likely make a separate portal, but how many people will actually go there? The other "portals" Facebook currently has like shopping, offers, games, etc are not very popular and hard to integrate with the stream.
Also the huge hurdle is getting a video app onto all of the players out there. Android TV, Apple TV, Roku, DVRs, Bluray players, etc. That's... not going to happen fast. The only way you will be able to watch these videos is through a phone and that's not a great experience.
We'll see how they fare I guess.