International aircraft with PTVs no longer feature main cabin screens. In the First and Business cabin pax cannot be relied upon to remove the PTV from its stowage to watch the video demo. Therefore it is done by FAs in all cabins, accompanying the video with soundtrack over the cabin speakers. The video is designed to be heard and not seen for this purpose. The Economy customers with both a PTV in front of them and an FA
in their section have the benefits of viewing both as Thadocta points out.
Domestic aircraft feature both FAs and videos to maintain consistency and again this serves as a benefit as the pax may get more out of one or the other.