The alternatives are satellite phones, which on their own cost a lot of money and will realistically only be wielded by people who expect they might end up in an emergency situation rather than anyone who owns an iPhone. This expands the coverage for life saving communication vastly.
We also don’t know the payment mechanisms involved with this service other than they’ll be covering the cost of it for the first two years of ownership. It seems extremely unlikely that they’d simply refuse to connect people in actual emergencies. Much more likely is that there’d be a fee for its use collected after the fact.