OK, might as well be up front about it, I'm thinking that smartphone-based person overboard (POB) beacons, like the CrewWatcher™, have got to be the worst idea I have heard of in a very long time, particularly since we already have a much better alternative: AIS/DSC beacons.
In fact, the only reason I can come up with for why the former are even a thing, is that it is a manifestation of the smartphone addiction syndrome that many people have been worrying about lately. In this case the symptom seems to be:
I will buy anything, no matter how ill conceived, as long as it runs on my smartphone, and even though there's already a much better alternative available.
That was sweeping. Let me go through my thinking, and compare the two systems.
Update October 2021
It appears that CrewWatcher have gone out of business. Normally I don't wish business disaster on anyone, but the CrewWatcher was such a dangerous, and yet clearly seductive, product that I'm hugely relieved that it is no longer sold.
We will leave this article up since it explains how ideas no matter how stupid can still gain traction and how important it is to exercise our common sense around boat gear and particularly marine electronics.