It's the first time I've heard anyone suggest this. I agree with you that listening to a language through headphones is usually a lot easier than without them but don't you find that generally when you're listening to something with headphones, you're only listening to one voice? That's not usually the case in real life. The main problem (at least the biggest problem for me with a foreign language) is that there are frequently other people talking in the background, or there's music playing, a TV on etc. Those things won't go away just because you have some kind of hearing device. If anything, they'll be louder!
Student or Learner