The FAA are to be applauded for moving ahead with this relaxation. I do not have problem with electronic non-transmitting devices nor those that operate quietly. However, my airline says that these things shall turned off whenever the seat belt sign is turned on, so that's my company line and I stick with it. But the reasons for doing so are lost in the mists of time, if they ever existed in the first place. Some say it's to create an environment so you can get a person's full attention, others say it's so the passengers will listen to the (old fashioned and rather pointless) "Safety Briefing."
What the industry really needs is research into the modern person and how we should go about delivering some snippets of quite important information which may save their lives. It is patently clear that we are not doing a good job with real people when you look at clips of recent evacuations - Jet2 @ GLA, the Cactus in the Hudson, BA @ LHR, UTair @ VKO etc... This is not the result of mobile phones, tablets or laptops - just poor and/or irrelevant message delivery and dreadful handling of passengers goods following an incident.
As an industry we can and should do better.