The reason Bitcoin is needed is because we need good money.

With dollars you are funding a lot of bad stuff, like wars, invasions, and it is money that you do not control.
With Bitcoins the rules of the game are clearly defined.

It is about freedom to do things better.

Also is depends if you believe if money should be based on debt or not.

Also you are standing to the man and telling him you can do things better not only with words but with action, and I think he is beginning to learn to listen.

Also if we compare to what the US constitution defines as money neither the dollar or bitcoin comply, but at least bitcoin comes closer it terms of compliance.