eSIM vs physical SIM

Not because of the format. Signal and speed come from the network the line registers on, where you are standing and how busy that cell is. If an eSIM and a plastic SIM sit on the same network in the same spot, the result is the same.

On most supported handsets, yes: let the travel line carry data and keep the home line switched on for calls and texts. Turn data roaming off on the home line so nothing is billed at your operator's rates. How many lines can be active at once depends on the model and OS version.

It depends on whether that plan and provider support a transfer or a reissue; not all do, and removing the profile from the old handset is usually irreversible. If you know a handset change is coming, ask before doing anything to the existing profile.

Most traveller plans are data-only and carry no number for regular calls or texts, so calling happens through internet apps and SMS codes still rely on your existing number. Where a plan does include a number, its own page will say so.

Install before flying, while you still have WiFi you trust, since installation needs an internet connection — then activate the line on arrival. Installing is not the same as activating, and when validity starts is stated on the plan's own page.

Either use a physical SIM as normal, or carry a spare handset that does support eSIM and share its connection to the main phone over a hotspot. There is no way to add eSIM to hardware that lacks it, so confirm the model before buying a plan.