- e-sims make it much more difficult to swap sim cards between devices.
- presumably border patrol wants to see his photos, social accounts, and email. A separate device with a copy of the information they want isn't a defense. Creating fresh travel-only accounts is tedious, b/c fresh accounts aren't connected to your friends or network (with whom you'd want to share your trip with).
you could login to your stuff after but the point is to minimize damage when you do lose your device abroad
laziness isn't an excuse and if you do want access to your phone or device at home you could setup that as well