IFE is great when travelling Long Haul.
If there are some noisy kids near you, the headseats can help deaden their noise as well as keep the little darlings occupied on doing something else than kicking the back of your seat.
I agree that it's a pain if the AVOD is under the seat in front of you but IMHO if you're on a plane for more than 6 hours it's essential in alieviating the boredom.
I always bring a book along but with narrow seats on some aircraft you can struggle to turn the pages.
The only time i think IFE is waste of time wis when you are on a plane with the drop down screans as you are always either too far or too close t the screan or there is omeone taller than you in front.