In the instance of circuit failure or abnormalcy, with rising current, the increased current in the circuit may damage the device or important components or even burning of the circuit which may cause a fire.
The fuse breaks the circuit if a fault in an appliance causes too much current to flow. This protects the wiring and the appliance if something goes wrong. The fuse contains a piece of wire that melts easily. If the current going through the fuse is too much, the wire heats up until it melts and breaks the circuit. Thus play a role in the safe operation of the protection circuit.