There's actually some really interesting dynamics you can create, using the leverage you can create by building a big stack early in a rush session. I'm sure it's not as applicable at 10nl and 25nl. I can't do the explanation of it justice - Marshall28 had some great coverage of it.

All in all though, I'm not sure about it being just a fad. It gives action to the action junkies. As long as there's a healthy collection of said junkies populating the tables, rush will stick around.

Just look at the success super turbo and don sngs have had.