Paper needs no battery. Paper needs no network coverage (not Wi-Fi) Weights compared: iPhone 6 4.55 ounces Paper notebook (example) 3 ounces Summing up the

Paper needs no battery. Paper needs no network coverage (not Wi-Fi) Weights compared: iPhone 6 4.55 ounces Paper notebook (example) 3 ounces Summing up the risks of flood+fire+critters you have a fraction of the risk for "falling to ground and break screen"+theft+malfunctioning. You'll need a pen or pencil, though.