Image hosting is easy, if you don't care about losing money. As long as you provide direct links to images, you're better than everybody else.
Video hosting? You need a good player (nothing will ever top YouTube's) and a good CDN. That's a tough nut to crack. Especially for a company with no money.
Main project is a sinking ship (cf. % of usage), most of their big projects have failed and closed in the last years (mobile, email client, persona, etc), they are caught in a major rewrite of their main project that may never end. It's a matter of time they stop getting funded.
This is my opinion; it is what I believe will happen, based on past and current events. Of course I might be wrong, or not.
They removed that possibility some time ago. Now if you disable your Facebook account, it's reactivated as soon as you log into Messenger. Tried it just a few days ago.
Video hosting? You need a good player (nothing will ever top YouTube's) and a good CDN. That's a tough nut to crack. Especially for a company with no money.