Question

why MCB is better than fuse

Answer 1

MCB is available at a certain rating (Amps)

So it’s the weakest link in your circuit in case of a short (live to neutral)

or overload (MCB rated for 15 A but your appliance uses 25 A, MCB will trip instantaneous to protect you and your circuit)

MCB can be used as an isolator in case you need to do maintenance on the circuit or replacing something

Answer 2

MCB is more sensitive to current then fuse. It detects any abnormality in the current flow and automatically switch off the electric current. In case of MCB, the faulty zone of electrical circuit can be easily identified.