But the esim doesn't need to be at the edge of the phone body. It enables significant simplification in layout design.

Sorry what? It creates a door, which needs to be sealed for IP rating, which needs to be located in physical relation to the edge of the phone body, needs power and data vias routed to/from which dictates the location of the radio, antennae etc. etc. etc.

It's absolutely impactful to the electronics design no matter the screen size, you just can't see all the decisions and compromises associated with it.