A320/b777 cargo compartment light control switch

[Danial9874]

Hi everyone,I am studying my diploma in aircraft maintenance at the moment and my instructor recently asked me a question

There is a ON/OFF switch on cockpit overhead panel to control the light of cargo compartment. ( that are built in certain A320 and B777 only )
What is the reason to built the switch on the overhead panel ?
*The switch stated IS NOT cargo smoke detector switches/ annunciation button.

Can anyone verify this ?
Anyone with information and willing to help out I'll greatly appreciate
Cheers:}

[LME (GOD)]

777 - does not have a cockpit switch for cargo lighting. There is are several switches at the entrance areas to the cargo holds for the lights.