Working with IoT cellular devices and eSIMs. It's not quite the 1980's. There is no scary or magic about e-sims. They are just SIMs. It's a chip that does all the things a SIM does (runs Java, yes ... a very stripped down Java), but has a very large reprogrammable area that stores all the data that is normally stored on a SIM card, specifically the secrets used to prove you are you to the network. When you enroll a device with an eSIM there is an API that you download the contents that would normally be stored into the SIM card and then ask the eSIM to memorize it for you.
eSIMs can actually be rather nice, in that they have the space to store many SIM "profiles." So if you are in Europe and have 2-3 SIMs for different carriers, your phone can remember all of them and then you just select which one of them you want active right now.
However, with Apple's walled garden things get a little concerning. You have to be able to offer an API/web service that allows the device (iPhone) to download the content of the eSIM. And, best I can tell, apple hasn't published an open protocol that they will accept for doing that yet (would love to be proved wrong here). This means that if you want to be a carrier that works with an iPhone, there are even more hoops to jump through to be "allowed" to download eSIMs into an iPhone.
Without a standard and well published API on how to offer the contents of an eSIM to an iPhone this does a real smell test of locking out smaller carriers, etc that don't have the IT staffs on hand to do the integration efforts that apple will demand to allow the iPhone to download a SIM from the operator's SIM API.
Apple cleans that up ... and a lot of the concern goes away.
It also eliminates the whole idea of burner SIMs. Can't just go plunk down $50 of cash for a SIM card that works for 30 days. Now you need an account on a web site and enter a credit card number, etc etc to get your 30 day SIM.
In the IoT space, I'm excited about eSIMs. Our devices work on farm equipment. It's a harsh environment with wide temperature swings and lots of vibration. And SIM cards are frequently not constructed in a way that is exceptionally durable. Any component I can solder down to the board increases the durability of my device considerably.
But it's not all just benefits. If I want to "just try" another carrier, I have a lot more integration work I have to do to "just try."