Well, yes, that's the original intent. However, how much sleep does the average person you know get? Are they not awake both before dawn and after dusk every day anyway? If that is the case, as I believe it is in most who consume the majority of power, then there is very little power Saved by messing with when things are light or not. What it does cause however, are headaches in every area where a timer or schedule is concerned.
In fact, if the 'savings' is so great, why don't we just set it so the sun goes down even later then it does now. Permanently.