eSIMs can be bad or good. I hope eSIMs eventually reduce carriers to a network you can choose to connect to, like your wifi. Choose it, choose a plan set, enter payment, switch plans, done. Hell you could have multi-plans simultaneously.
Travel to a new country? Same thing. No apps should even be required, it should be a native OS functionality.
TBH the entire concept of a SIM isn't needed anymore, cellular networks should become like wifi networks, and should be as easy to switch between too, complete with phone number portability.
People remember the bad old days of CDMA where a phone was bound to a network and there was no way to change it's internal esim. It doesn't have to be that way and most of the world doesn't do phone locking that much or at all anymore, much like your phone's wifi.
When cell networks become like wifi, the government excuses for KYC to buy fucking cell service would be reduced even further.