I'm in two minds about this.

I think it can be good and bad. I do believe that children should go to schools that suit there needs rather than just the closest school or the most "popular" private school. That said I think some schools (private included) do have a higher focus on certain areas (sports, arts, maths, debating etc) and if you have a child that excels in that area then of course picking a school that also excels in that area is going to be beneficial. I can see how it can be bad for a school's reputation if a school doesn't primarily excel in an area or has a low level of university entrants iykwim?

As a parent I am going to be looking at these areas, and yes whilst they aren't a business I do think if they can't cater to my child I'm not going to send them there.

Here in Melb we have the Age "Good Schools Guide" which gives a breakdown of what each school offers the number of students etc.