Every time I fly in an airplane that has an In-Flight Entertainment System (IFE) that consists of screens embedded in every passenger seat it is only turned on a few minutes after take-off and turned off a few minutes before landing? Why is this?

My limited knowledge of the system tells me that it should not interfere with any of the other on-board systems and thus it should not matter whether the system is running or not. The only reason I can think of is safety, similar to the question of why lights are dimmed during take-off and landing.