Google Maps: Why should I load my InfoWindow via AJAX?

I stumped upon the following Google example page of loading my map marker InfoWindow using AJA开发者_StackOverflowX, instead of preloading the InfoWindow ahead of time.

http://gmaps-utility-library-dev.googlecode.com/svn/tags/extinfowindow/1.2/examples/ajaxContent_packed.html

However, I don't understand the use case for why someone would want to do this?

Does it perform quicker loading the content of the InfoWindow via AJAX? etc?

It is not quicker, but if you have many markers, it will make the initial page loading faster.