Grave Titan offers a good amount of defense, a good amount of value and a very snowbally win condition that can attack while retaining defenses
You get to draw the card no matter what and it can even help you cast an additional land, maybe in a color you need
Not only that, but other flying creatures you control get +1/+0
(Each of those creatures can deal excess combat damage to the player or planeswalker it's attacking.) Whenever a creature you control with power 4 or greater enters, draw a card
What differentiates it from other artifact payoffs is that it both costs a lot of nominal mana and protects itself via ward
It gives you a free card in your graveyard, which was important in powering up Treasure Cruise and Dig Through Time, not to mention the delve cards that remain in the format like Gurmag Angler and Tasigur, the Golden Fang