DHDD is a very good card when used correctly. The deck based around him is supposedly dead due to banlists, but there are many effective ways to use him. For anyone unfamiliar with the card, his effect only activates the spell's effect, with no regard for conditions or costs. This makes it very good with certain cards.
Magical stone excavation is a very common usage of DHDD. This is because he simply allows you to pick up a spell from your graveyard. He has no regard for the cost. He just takes whatever normal spell he wants and uses it. So magical stone excavation, allowing you to pick up a spell from your graveyard, is a perfect mill with diamond dude due to not have to discard 2 cards to pick up your monster reborn, heavy storm ETC.
So, DISCUSS. NOW. This card is awesome.
Spoiler :
Magical stone excavation is a very common usage of DHDD. This is because he simply allows you to pick up a spell from your graveyard. He has no regard for the cost. He just takes whatever normal spell he wants and uses it. So magical stone excavation, allowing you to pick up a spell from your graveyard, is a perfect mill with diamond dude due to not have to discard 2 cards to pick up your monster reborn, heavy storm ETC.
So, DISCUSS. NOW. This card is awesome.