Ego boosting, and to be honest that about sums it up.
Most of your traffic you will want is from Google, and Google has no connection to Alexa, and all they do is gather user data from users who have installed their toolbar.
As a fair amount of people have then its a sample set of all users on the internet which enable them to produce a model of what are the most popular sites in the world. Is this of any use to you? It does not matter really if you #1 million or #10 it will not bring you any more / new traffic.
You could just look in your analytics to see if your traffic is rising or dropping.