Though I've flown on KE and OZ a lot, I've never been tempted to buy DF because the prices weren't better than in the U.S. So I don't really know much about how DF works.

So here's a stupid question: In addition to getting you out of the import duty, does buying, say, booze DF allow you to bring in more than you'd normally be allowed to?

And, yeah, one 30 second announcement and the FAs making a pass down the aisle is a small price to pay for a better overall flight, at least on KE.