It's the nature of the computation that bugs me.

We have a network growing exponentially relying on the fact that we're hashing random numbers. Academic research aside, it sounds very useless.

That has nothing to do with the way banks are doing their maths or maintaining their infrastructure. Again, I'm also very grateful of bitcoin demonstrating we can exchange value without a 3rd party, but it looks like nowadays we could do better.

Now in regard of the destruction of ecological areas, mining gold etc... I simply agree with you.