Good topic,
@Avery - it's definitely something that is under-referenced.
In fact, to go beyond the scope of the article a bit, it's not just for graphics (although that's the usage that requires any editing outside of RPG Maker). Using placeholders is a good technique for anything that's holding up your project.
Not sure how to balance your enemies' and classes' parameters? Make them whatever until the maps and story of your game are finished.
Not great at mapping, or not sure what details you might need? Make simple maps for each place until you've created all of the locations you'll need to finish your game.
Don't have the dialogue for this NPC written out fully? Just talk to them and advance your story trackers for now.
It's easier to fill in details and specifics once you have a framework constructed.