I think this is a peculiarity of the short-term travel eSIM providers (like Airalo). If I recall correctly, when I went to Bermuda, the Airalo eSIM would route the traffic through Isle of Man. They have some of the most odd agreements with random telecoms to get coverage and cheap rates.

Partly I think it's skirting around local regulations (e.g. if a country required SIMs to be registered with the owner's information, but you provision the SIM from a nearby country's telco and route traffic through there maybe you can get around it).

But as far as I understand this has nothing to do with eSIMs and a lot to do with Airalo trying to cover every corner of the world for cheap.