Don't expect noise cancellation to work with an adapter. And draining your device faster is never a welcomed feature. Trash I tell you!
I would only need noise cancellation when i'm on the plane watching movies on my iPad or listening to music on my iPhone. Relevant concern for people that watch in-flight movies or use their laptops, neither of which apply to me so not an issue.
I'm not concerned with the battery drain if it saves me from having to charge the headphones separately. ANC typically uses very little power, hopefully that will carry over to the iPhone's power consumption. I carry a battery pack in my bag when I travel in case I have a long day and need to juice up anyway.