I think this site is one of the worst things out in terms of comparing schools in which to send kids to.
The site only compares results from the NAPLAN tests sat by year 3,5,7, and 9. It doesn't compare the type of teachers, the feel of the school, how different kids adapt to academic environments etc. Not all kids perform well under pressure (I was one of those) so things like that will also affect the results.
I also think that you can't compare schools that recieve allot of funding (gov or not) to those that don't.

I think the only thing it does benefit is those people who are working to create programs and gain funding for these children and young people to help them improve on these results