Yeah, it's a nice concept when you have good rolling bigs and strong shooters setting the initial screens. In the Celtics case, the fact that Kemba can often gain an advantage off just the initial screen opens up a lot.I may be wrong but I think Miami was using the double drag roll to consistently get points against Philadelphia a couple of nights ago.
Re TL in a post above: you'll actually see in that video times where he has trouble executing the screen/no-screen read. I think that's an argument for playing him more rather than less (to gain experience), but YMMV, and it's a moot point while he's hurt.