My HP Pavilion laptop has a power light on the switch (a slide-and-release switch). This light is off when the computer is off or hibernated, constantly on when the power is on, and it blinks when the computer is suspended. Now, I figure that as far as the hardware is concerned there's no real difference between "hibernating" and "off". But why should the light blink when it's suspended?
What reason could a user have for differentiating between "off" (or "hibernating") and "suspend" states while the laptop is closed?
Most operating systems will automatically change to hibernation should the battery get too low, so user intervention for the sake of power management is unnecessary. I don't think there's any problem if the user flicks the power switch while the laptop is waking up from suspension (thinking that they need to manually wake it from hibernation), although avoiding this is about the only reason I can imagine. But if that's it, surely a better design would be to simply power up the machine from whatever state it's in upon opening.
(I hope this isn't too subjective... it's something I became curious about, and thought there might be an objective reason for it.)