The reason for devices being stowed during take-off and landing roll is not because of their electronic danger but because they can become a physical danger in the cabin and become airborne and possibly injure someone.
Preventing objects flying around is a good reason to stow anything, electronic or not.
The specific reasoning behind not allowing electronic devices below 10,000 feet, is to try to avoid any extra distractions to the pilots during critical phases of flight... whether it's a strange-acting navigation instrument or interference in their headphones while ATC talks to them.
(There's a reason why takeoff and landing are called "critical phases of flight". It's because even a short distraction can have really bad consequences, as has been proven over and over again.)
Thankfully, contrary to popular belief, a cell phone not in airplane mode does not take down a jet.
Not directly, but if it stomped on a critical ATC transmission, it could do so indirectly.
And that's what non-pilots don't seem to get.
It's the possible distraction that can be a problem. For example, the reported cases where devices might have caused false TCAS alarms, forcing the pilots to instantly decide whether to follow the robotic anti-collision commands, or ignore them as a probable passenger device interference.
People often say, "Oh, well it didn't bother ME, so it must not be a problem"... never knowing what situations the pilots might have had to deal with.
Airlines will have to certify that their aircraft can tolerate any radio interference from the personal electronics devices,
That's a big requirement. It's not only expensive to do, it's impossible to fully test, and it's possible that some older airliners won't pass or even be tested, leading to mixed up rules within a carrier.
The upshot is, what would this allow? I mean, you couldn't let people use devices from the gate to take-off, because the flight attendants would have to walk the aisles while moving, or stop the aircraft at the end of the runway while making sure everything was stowed again.
This smacks of a feel-good announcement pushed by Congress members. Remember, this isn't the NTSB safety folk giving permission. This is the politicized FAA, who wants to promote air travel even while allowing ridiculous addon fees and smaller seats.
I think that it should be the other way around. I think that each airliner should be certified by the manufacturer, not by the users.