These days I only use FB Messenger for the small few number of friends who still use Facebook and send me videos on there. But the experience of watching videos sent to you is so incredibly clunky - Messenger itself apparently can't just play the video, it has to kick you into the Facebook app, so watching 3 videos someone sent involves 6 jumps between apps. And the player in the Facebook app seems broken, seemingly sometimes there's no scrub bar, or if there's supposed to be one it doesn't work.