I don't need to do anything to connect to my providers public networks. The keys are (I'm guessing) just stored in the SIM card and I'm automatically connected when there is WiFi available. LTE being super fast and all, I don't mind not using my data plan and having a low latency, high bandwidth connection without even lifting a finger.
You also seem to overestimate how many people can afford a data plan like we (probably) have. Or just young people. Or people who don't use the Internet that often at all. It is probably not ment for the average HN-reader.
>>The keys are (I'm guessing) just stored in the SIM card
They're not. They keys (and many other things) are stored in "carrier settings" that your provider pushes to your smartphone. In the past we had to set things up like APN & etc manually for the internet to work but not anymore with the settings being pushed automatically (if the provider supports it).
On iOS you can view the current version of pushed settings by seeing the Settings > General > About -> Carrier option.
"Carrier settings updates are small files that can include updates from Apple and your carrier to carrier-related settings, such as network, calling, cellular data, messaging, personal hotspot, and voicemail settings". [1]
You also seem to overestimate how many people can afford a data plan like we (probably) have. Or just young people. Or people who don't use the Internet that often at all. It is probably not ment for the average HN-reader.