It's not exactly "satellite network", it's piggy-backing on an existing SAR reception infrastructure that used to require somewhat expensive dedicated devices.
Not sure it's a good idea, I'd expect a wave of SAR requests for not real emergencies.
ADDED: There are also perhaps more common situations like going off the road in a snowstorm.
A PLB usually also has a radio transmitter on it that allows rescuers to direction-find your location.
https://www.apple.com/newsroom/2022/11/emergency-sos-via-sat...
If I am getting this right, Apple and other device makers would have some kind of beacon registration for every single device it produces with the feature ?
https://9to5mac.com/2022/12/14/iphone-14-satellite-crash-det...
Which is a pretty neat capability all things considered.