If I know the true cause, I have better information, and can make decisions accordingly.
Maybe I should tell somebody not to wait for me, because I know the delay will be long... perhaps I should rearrange future travel while I can... maybe I should cancel a hotel booking because I won't get there in time
If captain is frantically trying to get an aircraft fixed... he/she needs to be left alone. Gate staff who are just playing with their phones while they wait are fair game for cajoling for info. The question is how to cajole that info out of gate staff...