USA phones not supporting a physical SIM card is certainly a disadvantage for those traveling worldwide. In many countries it takes no time to buy a local SIM card, put it into your phone and have a local phone number to avoid high roaming charges especially for data.
Also having a physical SIM card makes switching phones possible in seconds. I have a spare phone at home and when my phone needed servicing, it was an easy job to put my SIM card in my spare phone and go back to being online in seconds. Good luck with an e-SIM, especially if the phone is completely dead.
Luckily, iPhones in many other countries still accept physical SIM cards so far. Maybe in the future, activating the second e-SIM locally will be equivalent to buying a prepaid physical card but until it is available worldwide, I think deleting the physical card is a disadvantage rather than an advantage at this point.