What is the purpose of "typeAndWait" command in Selenium IDE?

I am just thinking about command typeAndWait in Selenium, because I cant figure out any real purpose of it.

In what situation you type in some input and then the page immedeately starts reloading? I can imagine AJAX, but in this case the page doesn't reload - which is the reason, you have to use waitForXY commands instead of xyAndWait when testing AJAX...

But it was a long day today, maybe I am just dull now and the answer is quite obvious...