Advantage of Vacuum Contactor

Oh, at a guess, the need for more components and an electrician to change the fuse when it blows, whereas the circuit breaker might be reset by an operative. Economics?

It is 10-20% cheaper. Motor with frequent start-stop shall use vacuum contactor instead of circuit breaker. Vacuum contactor is designed for millions on/off operation while CB isn't.

That's a sweeping statement.

Vacuum contactor is designed for millions on/off operation

Whoa there, that isn't true for high voltage vacuum contactors and switchgear at all. Tens of thousands yes, but not millions.

Electrical endurance :

a contactor is rated at a minimum of 300 000 operations (Schneider SF6 rollarc contactor) and easily up to 1 million for vacuum contactors, whereas circuit breakers have a rated endurance of 10 000 operations.

Downstream cable protection :

In case of fault at the motor terminals, for instance, a fused contactor will limit the I²t , when a circuit breaker will have much slower protection . A fused contactor will allow you to size the conductors at the cross section needed by the motor amperage, withous having to take care of their short circuit withstand .

Vacuum contactor is planned for millions on and off operations. Contactors are useful in commercial and industrial applications.