Yes, contrary to the american funny folklore around tinfoil hats, a tin (or aluminum) foil neat wrapping around your phone (preferably with a layer of cardboard or other isolator underneath to guarantee a nonconductive gap) will definitely save your phone from a typical EMP attack threat. Two perpendicularly wound layers are better against human errors. But if it will not - most likely you brain electricity wouldn't survive either to use it afterwards anyway Mu-metal? It's for the scientific equipment isolation from slightest magnetic fields during precise electromagnetic measurements/experiments. Yes it will work for EMP protection as well, but not much better than an aluminum foil. In fact, all you really need to protect your equipment from EMP is a low electrical resistance conductor, looped on itself. That's all what elementary physics require. The popular among preppers garbage can is actually inferior to aluminum foil wrap, as it's made of a much less conductive steel and zink. The best option would be a silver foil. However, a garbage can is more convenient for fast tossing the stuff in as well as for a long term storage if done right (aluminum tape sealed lid gap).

The physical size plays the major role here, as the more the surface the higher gain of the resulting antenna for "EMP signal reception". For example, the Solar Flare produces very similar to the EMP threat, but it will affect severely only large power grids, not cars or smartphones - exactly because of the size of an antenna the grid resembles. Also, the smaller size is easier to protect, as you need a smaller (thus easier to improvise) faraday cage.

Smartphones are smart, because they can be used in a smart way. For example, I have a 22Gb sized website, with thousands of survival books and papers indexed, directly mirrored to my smartphone storage, so even without the internet connection I can browse it on the phone as a regular website. Same for the street level maps of the entire US, Canada, and Mexico - all offline... Paper maps? I don't aware of a truck which can load so much paper at once. Also I have around 300 apps installed, many of them have survival use even if just for fighting the boredom. Leaving the weight of books aside they are prone to moisture, mold, insects, and fire. Also they have a value even for dumbest looters for their paper (cigarettes, kindling, toilet paper, wrapping goods). Besides, it's easier to protect a 128Gb T-flash card with millions of pages on it than even smallest 100 page book - just swallow it

Yes, even my 4 years old Android smartphone has a real barometer, thermometer, and humidity sensor. That predicts severe weather changes quite reliably as soon as you have calibrated the local pressure range:



Anemometer is harder to implement in a pocket device, but I saw them as a standalone pocket devices (not that crucial for a local spot weather forecasting, more like for its propagation in the region).

Don't need biometric sensors on you? What about assessing and monitoring your unconscious buddy condition?

Regarding the recharging. I've started with Palm OS handheld (1999). In the past November I unboxed my Palm VIIx, installed two AAAs, booted it, and restored from backup flash "disk" - it works flawlessly. I have Sony TH55 riding in my astronomy bag all this time as a spare star chart (includes plenty of survival stuff as well). It's 11 years old Palm OS wonder. Charging it and restoring from backup every 6 month. The integrated LiPO battery still holds the charge for just a little above an hour of WiFi, but it works indefinitely when connected to my 8Ah powerbank with USB cable connected. I'm sure that modern batteries will continue to be usable for at least the same period of time (I have 2 spares, one is EDC, another is recharged to 60% every 6 month). The external power option will work even if the battery charging MOSFET will ever die (I have the external battery charger as well).

Mechanical issues: as I've said, with the proper phone case the fall into a creek will have no effect on the phone at all. The phone casing, which I've already mentioned (Otterbox defender), withstood falling from about 5 feet height to a concrete twice without any consequences, and that's not a small phone, but a 5.5" screen phablet. In fact, I'm protecting it probably even better than my own ribs when in the field (both times I dropped it at home). I do see it as the best replacement possible for books in a SHTF situation.

Kids can be a pain if not entertained. But modern phones are sturdy enough to withstand any abuse by a typical child. Surely if you refrain from offering it as a soccer ball substitute. The valuable data is easily protected by using the multi-user profile feature (on Android, iPhone is an epic fail for almost any of the above), which has the special "kids mode". Besides, not only kids need some entertainment time, I have a huge scifi library on my phone, as well as Monopoly, Chess, Holdem, and other table-like multiplayer and single player games for every age.

The bic lighter is an irrelevant comparison, it's more like a zippo lighter (by the way, it's a great hand warmer if you have some heavy app to release the good heat from the silicone ). But I see my smartphone more like an extremely knowledgeable and resourceful buddy (it can even speak and talk to you, you know?). Add this and your phone can get "legs" and "hands".