Together with kernel checkpointing/restart feature, what LWN.net covered in an article a while ago, this could be another possibility to extend battery life ie. when lid closes, checkpoint processes with open file descriptors and below X and shutdown, and then up again in 5 seconds.
At least the fast booting seems to be a simpler way to achieve practically the same goal as the suspend/resume operation has. But the process checkpointing/restarting feature is yet taking its baby steps, so it is practically non-existent. Too bad. I'm haven't found myself comfortable with session features of KDE or Gnome and thus I'm totally relying to suspend/resume to get my desktop back to state, when I left the desktop. And I reboot as seldom as possible - I actually hate system updates requiring reboot or losing the desktop state.