If you've traveled internationally, likely you've used a SIM card for local data and calls. There is a nice ecosystem around SIMs with a wealth of easy and affordable Pay As You Go (PAYG) options.
But the newer iPhones did away with the SIM slot if favor of some new eSIM hotness. Apple has all kinds of info claiming they have good international support, but I found reality falls short.
- Only a few carriers support eSIM's,
- The few that do require a contract. A tourist or student studying abroad is better served by a PAYG plan, and
- Even if you can stomach a contract, that would require a UK bank account; no way to easily pull that off.
We ended up falling back to international roaming. It works but is expensive.
I think Apple made the wrong call removing the trusty old SIM tray. Clearly the new models can be made to work well with it, since how they are sold in the UK. If you're unlucky enough to have bought your recent iPhone in the US, you're out of luck.
I this is an example of Apple bad tendency sometimes choose form over function, "courage" over usability.