Answer:
This is quite tricky to answer knowing that biodiversity is a great factor to our existence. Remembering that biodiversity is necessary in ecological life support, it is hard to put up a contrary argument. However, just for a while, let's feign ignorance in its significance.
Diversity. Loss of differences in creatures and lives. That is, saying that the loss of it does yield some advantageous opportunities. For instance, massive land spaces are made vacant, meaning, we, humans, can occupy more for the sake of our living. Added to that, we can monopolize living quarters for our own sole good. It may even go as far as feeling greater satisfaction--just us, people of the world.
The loss of diversity counts us closer as the primary living on the top of the food chain. No other predators. But hey, ain't it good that we are on the top? Only us.
Researches even tell that the end of the world is far ahead of us. A century perhaps. A world of growing human communities. Only us.
Okay. I'm going to stop now. Biodiversity is important. It is almost against everyone's ideals.