Asking people to put their things away during take-off or landing makes complete sense, and anyone that doesn't want a broken phone or tablet or nose should be doing it anyway. The jolt can send devices flying out of people's hands (mostly on landing). People are not coordinated and will flail and drop things when off balance. I saw some woman smash the guy next to her in the face with her tablet during a 'rough' landing about a month ago. The guy handled it well and shrugged it off, but you always hear the horror stories about people being thrown off of planes and arrested after fights over far dumber things.
Stopping things from flying around the cabin, hurting people or breaking things has always been the reason behind them asking you to stow your belongings during takeoff/landing. They don't want you having books, bags, or other large flat hard objects just loose in the cabin either. This really has little to do with being allowed to talk on your phones, or ignoring the safety speech and much more to do with common sense.
Put the stuff away. You can take it out again 5 minutes later.