In second language acquisition I think flipped classrooms are useful. L2 learn at varying rates so allowing a re-playable video would help students be on the same page. The videos would also allow students to spend valuable class time speaking and listening rather than just listening to the native speaker lecture. My students writing available is probably at an intermediate level but some have trouble putting a proper sentence together out loud. The students could spend the class time applying all the things they learned in the video and work to even out their speaking and listening ability.
I have really enjoyed learning more about flipped classroom and am hopeful of finding information about using this concept towards language learning.