In so-called "single page applications" for the web, I am seeing a trend, especially in demo applications, where any navigation between sections of the application/site involves a css animation of a page content "chunk".
To be fair, these animations are often subtle enough so as not to be annoying, yet at the same time I have to wonder, isn't this nice little trick going to start bothering users? It gives demo apps a certain "cool" factor at first glance, but imagine if you are a user who has to use an app like that hours a day. Would you really want a .3 second page slide effect every time you visit a page you have visited hundreds of times before? Gmail is a single page app, and if Google wanted too, they could add all sorts of unobtrusive animation effects as content changes. Yet Gmail avoids this; Google uses a small yellow progress indicator in certain cases, but that's it.
So my question is: for a content-rich single page application, can any case be made from a design or usability perspective that it would be good idea to include subtle page transition effects?
(I am aware of this article: Smart Transitions In User Experience Design, but do not see that its points, such as animated scrolling, relate 100% to a single page app like Gmail .)