> There are Iridium-based two-way messengers on the market without an externally visible antenna.

I currently own a couple and have owned a bunch of other devices in this category. Have you ever looked at a tear down of one of those devices? Now compare that to a tear down of an iphone? Even supposing Apple can design a much smaller antenna, where is it going to fit? What’s the battery life going to be when it has to send messages periodically (until confirmed) at MUCH higher output power?

What if this is an emergency situation only thing. Say your phone detects you took an impact (car crash) or fall (hiking), it can start sending out emergency text messages with location data periodically until the battery dies. Tie this with vitals on an Apple Watch and it could prove very helpful in extreme situations.