Cards from your hand are also considered 'Sent', however, 'Sent' cards are not automatically classed as discarded. Similarly, when a card is destroyed it is considered 'Sent', however, 'Sent' cards are not automatically considered 'destroyed'ref.
Proper knowledge of the difference between 'Sent' and 'Destroyed' could mean the difference between a win and a loss in playing the game. For example, some of the "discards' them to the graveyard while the latter 'sends' them to the Graveyard." series of monsters have their effects activate when they are discarded to the Graveyard. They activate with the resolution of " " but not " " because the former '
Another example is the effect of "". Because its effect sends monsters to the Graveyard, it cannot be chained to by the effects of " ", " ", " ", and the like because it does not 'destroy' the monster.
Yet another example is why the effects of "Tributed. Their card texts state 'When this card is sent (from the field) to the Graveyard...' Therefore they do not have to be destroyed unlike cards such as " " and " ".", " " and " " activate when they are