What does that mean for you?
Bitcoin participants exchange information through a network. A disconnected device cannot by itself tell the rest of the network about a payment or receive the latest history.
Some arrangements keep signing keys offline while a separate connected device passes payment information along. That is a distinction between approving a payment and sharing it, rather than a promise of offline settlement.
Can you picture an example?
Imagine your phone loses its connection. The screen might still show an earlier balance. That screen alone cannot tell you whether a new payment has arrived since it last received network information.
What should you remember?
Losing a connection does not erase bitcoin from the shared record. When you read a balance or status, ask whether it is current. This guide does not describe alternative broadcast systems or give an offline setup procedure.