There are requirements for performance - appropriate to the function.

The electronic flight bag interface is not used in emergencies, one of its main uses is in planning and submitting flight plans before takeoff, and it's generally not used for actively flying the plane.

Exactly. In an emergency the last thing the pilot wants to do is navigate a map interface for anything. Better to just select the alternate flight plan that was setup hours ago during flight planning.

That's why pilot are mandated to do simulation tests every few months

That assumes that deep navigation of a UI is necessary or desirable in an emergency. I think most of the important stuff is done with the main controls, dedicated switches, and screens/dials that are always on and ready.