Disagree.
See my post above if you haven't already.
Two-way communication is a hugely important, lifesaving capability.
A breadcrumb trail, real time location, messages with your wife and others, and the SOS button are all separate and distinct functions on the SAT messaging devices.
When you push the SOS button on the InReach, a message with your location is sent to the IERCC which will ask you to confirm if you are having an emergency and then ask a bunch of other questions about your location, condition, equipment and supplies all while contacting the agency responsible for search and rescue in your area and getting them rolling. What this response looks like, who mounts it, and how long it takes varies based on where you are at.
Being able to dialog with the SAR responders about the nature and condition of any injuries, weather and conditions at the scene, etc. are critical in helping the SAR teams prep and execute their mission and in doing so, increase the chances that you will survive.
Regarding signal strength of given devices, the more important factor is the satellite network that the devices uses and availability/proximity of those satellites to your location.
Garmin uses the Iridium network and PLBs use the SARSAT network. Both have a similar number of satellites and are equally as reliable. Terrain and location of the device is usually the limiting factor when it comes to the device communicating with the satellite network.
Personally, I have experience far more false/inaccurate location reporting incidents with PLBs than with Iridium network devices. Most of those have been with downed aircraft in mountainous terrain. Again, in my mind, this reinforces the need for two-way comms. If the SAR team can't find you based on a weak PLB signal, you are hosed. If they can't find you with an inaccurate location on the InReach, they ask you for your coordinates and come pick you up.