On some machines, standby and hibernate can disconnect LAN connections (LAN card no longer active in communicating with machine), so you have to re-boot to get them back again.
If I have lots of windows open that I'm working on & want to come back to them without having to save/re-open them all, standby works well for me. However, if the battery on the notebook, or the UPS for the desktop, ever died while in Standby, I'd lose everything because it's NOT written to the HDD in Standby.
In Hibernate, the entire session (including all windows, applications, data, etc.) is written to the HDD. If power fails, it doesn't matter since it is all restored from the HDD.
Does that help explain better?