Dropping a phone on a nice sheet of plywood is ridiculous, put it in your back pocket, get on a motorcycle.
Lay the bike down, call the medics, in a foreign country! Try and give the helicopter dispatcher your MGRS location. You may laugh at my old flip phone but the medics wiped the Blood off it and called my wife, and it was a bicycle accident. I have four garmins and I can use MGRS with them. I still carry a paper map and a Mil protractor, I don't need to worry about battery life. If you want to design an app, I want to read usgs maps on my iPad. Give me another app with a grid with one KLIC, kilometer spacing, and when put a pin in I get eastings and northings. Have it talk to my other devices, so when the battery dies I can put two AA batteries in the old garmin and it works fine. When you deal with an old pilot it's not GPS it's a PLGR!