Well, it is "wasted power" for sure. My 6000 kH is benefiting me only while consuming energy that doesn't benefit anyone else. Would be cool if there was some benefit for sure.
The benefit is the entire bitcoin infrastructure. Mining is not solving useless calculations, it is processing the transactions needed for the currency to work. Instead of paying money to large banks for all the infrastructure they require, we are using some computing resources.
This is a solid point. I agree that it'd be nice to have a side benefit (like protein folding or something) but what we're doing is acting like the bank. It means less fees since we handle all the work (er, our clients do), so don't think of it as "wasted energy," but rather "working for you."