What are the dangers of using DVD curriculum?

We are blessed in this country with an abundance of great Bible resources. I have been blessed by many of them. Our church uses DVD curriculum for adult Sunday School and Home Bible Fellowships quite a bit.

I've had this growing sense in me that we should be very careful to limit our use of DVD teaching (and similar) .

What are the dangers in the local body of regularly using a DVD curriculum or lesson? I really am hoping for some great answers.