I don't have any examples of any code bases that adopt this convention.

There are a few benefits in my mind including:
It is easier on the eyes. Having BIG_SHOUTY_WORDS in the code is ugly (on the web we associate all caps with shouting) and probably draws attention away from the more important parts of the code.
The other reason is that it allows you more freedom to write expressive variable names. To use the example from our previous discussion. I think `setSelectedTab(Home);` reads better than `setSelectedTab(TAB_INDEX_HOME);`