this is a real tough point to argue. Your point is flat out wrong. al Qaeda has never operated as a hierarchy organization. In the vernacular, we in the counterinsurgency community call al Qaeda a multi-channel network.
That said, the indirect components can be speculated endlessly.
1. How will this affect the average american's attitude toward the war in afghanistan, which isn't really a war but a counterinsurgency operation, change? Make no mistake, we are still in Stage 1 COIN per Field Manual 3-24. We have the other 4 LLO's (the first one being eliminate insurgents, the other 4 being training afghan army, building schools/infrastructure, securing population, installing competent government). Maybe some will think we have the bad guy now, let's go. That would be a mistake given the extracted nature of counterinsurgency.
2. It definitely bolster's America's power projection credibility. For a long time, as everyone knows, our military has been seen as so huge, so dominant, so powerful, that all other states combined could not defeat the United States. Yet small insurgencies have always been America's weakness. Now that we have shown that we can eliminate insurgents without 500,000 troops on the ground, it makes us look stronger. This can attract more international cooperation and domestic support.
al qaeda's side:
1. their symbol and leader is dead. for more of this argument see farid zakaria.
2. America now seems unbeatable.