I'm in the UK, I use mobile for getting bonuses, as the FB offerings are just surveys and reviews.
I can get enough to do 2x training bonus twice, and about 20 green/blue pack boosts.
I haven't seen any difference in number of videos, but they've changed a lot recently. My bugbear used to be the 'We're under attack' game-ette ones which used to be 4 out of 5, but now I hate with a vengeance the 'Touch sense' ones which vibrate your phone...
The one I have noticed that has disappeared is the holiday location adverts, some of which were much, much longer than the 30 seconds of the usual viseo.