The most important part of an eSim card is the profile information stored within it. The profile contains the necessary network credentials and settings that allow the device to connect to a specific mobile network operator. It includes essential information such as authentication keys, network access codes, and operator identification.

The profile determines which network the device will connect to and enables services like voice calls, messaging, and data connectivity. Without the appropriate profile information, the eSIM cannot establish a connection to any mobile network.

Additionally, the ability to store multiple profiles on the eSIM provides the flexibility to switch between different mobile network operators or plans without needing to physically change SIM cards. This aspect of the eSIM technology allows users to conveniently access various network services on a single device.

Therefore, the profile information stored on the eSIM is crucial for proper network connectivity and is considered the most important component of an eSIM card.