It can't really just count graveyard or if it does it's a total screwup by konami as there are all kinds of weird destruction conditions such as returning to deck, extra deck (fusion deck pre-synchro era), remove from play etc.
Actually no... if an effect does not say destroy a monster or card and a monster or card is not destroyed by battle then it is not destroyed, banishing a card is not destroying, returning to the hand is not destroying, tributing for a ritual or fusion summon is not destroying... on a side note... IF IT DOES NOT GO TO THE GRAVEYARD IT IS NOT DESTROYED.
I'm having an issue where I use the vassal + union attack + spell reclamation combo for over 10000 damage to win game but in the duel assessment, I don't get the 1000 points for victory by effect damage. Any reason why this is happening?