There are always people who are convinced there is a rational, polite, gentle and civilized way to stop a violent sociopath from raping their eyesockets.
We call these sensitive souls “Morons.”
They are the perfect demographic for this idiocy (a top pick among Kickstarter staff! I always ask the staff of what’s basically an auction site for advice on combat):
Read the article. The device is designed by people who have no idea what happens to the body when a dose of adrenalin is suddenly shot into the bloodstream and fine motor skills go out the window.
It appears to be sold as a stand-alone-solve-everything item which in reality means you friends and cops will know where to find your phone once they track it via GPS and with luck your body will be near-by.
Now, if flash-bang grenades were easily available to the public…. that is an app that would slow down an attacker.