In saying that Al Qaeda did not benefit from the attacks, you are applying western logic to eastern thinking. Groups like Al Qaeda do not consider the same things "beneficial" as we do. They gained fame (even if it's infamy), they gained money, they gained support among many (certainly not all) Muslims.
And for those under the leadership that were sucked into believing God supports their cause, they gained the belief in divine approval (rejected by moderate Muslim scholars/clergy). Their goal is not to win world support for their cause, but to continue being talked about, and to continue feeling relevant. With the attacks, they got that for a decade, though now they are on the decline.
It was also good for many people and industries. That does not mean the wanted it to happen or they were glad it happened.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.