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.