Agree.
Then the switch is just for maintenance, nothing to do with protection.
davidbeach hinted that a cable must come with an isolation.
If the switchgear is two lineups, a cable will act as part/continuation of the bus, will it need a CB in both sides? or just one CB and a switch on the other side for isolation? in case of a fault in that cable, the upstream breaker will trip to clear the switch bus side, as the coupler breaker breaks the other...but the power supply for the switch side bus is lost!...this is not the case for two breakers.
Reliability comes for a cost.
The case of interconnecting cable may be argued that a cable is always prone to a fault, not like that with a non segregated busduct (but a fault can still happen, rarely, very...), this very rare probability justifies the cost for two breakers?I doubt!