Unfortunately, the increasing prevalence of eSIMs in new phones makes temporarily switching to a foreign carrier far more inconvenient than "just buy a SIM at a vending machine".
The increased prevalence of eSIMs has made using a foreign carrier easier than ever. You don’t even need to find a vending machine or store. You can purchase your eSIM online before you even get to your destination.
The last time I traveled to Europe, I got an eSim for like $20, and they emailed it to me. I had coverage before the plane taxied.
How so? I have my US number on an eSIM. If I went abroad, the hardware slot is available. Or, pretty sure I can just add a second eSIM, no?
iPhones (and probably Androids too) support up to 10 eSIMs with 2 active at the same time, if I'm not mistaken. And you can buy data eSIMs before even leaving the country in an app like Airalo.
Yes, it's much easier to buy ahead of time in the app and have it automatically activate upon arrival, instead of having to find a kiosk in the airport.