That's not the single most ignorant comment I've ever read here, but it's very close.
You think systems knowledge and understanding is ridiculous, then?
I'm alive thanks to systems knowledge and understanding, several times over.
I'm very familiar with the school of thought that suggests one need no nothing beyond annunciators and ECAM messages...but I also strongly disagree. I don't think you can ever know enough about your airplane.
I also strongly believe that one who enters the forum asking an honest question deserves to get an honest answer, and not ridicule for asking.
No one should be ridiculed for asking a question. I think though the diverse answers above are all clear but both elaborate and concise. If I was tasked with operating an engine witn a CSD/IDG I would want to know why if given an abnormal indication it may fail (usually low oil quantity) but more importantly how to react, tasked with troubleshooting the more common IDG It's inner workings may be more helpfull. Once off wing the details of it's failure are more important in helping to look for the reason it failed. Everyone envolved has a different function, the guy who break's the machine down has little care about a simple "fail" indication, The guy who see's the fail light should not concern himself with the inner workings when he has an aircraft to fly, only react as the manufacturer and company tells him to. Too much thought can be dangerous, knowledge is an asset.