A 6/6 for 6 mana is pretty standard, but it also gives you an immediate buff to one of your other creatures
The drawback is that you usually have to pay life to use them but life is a resource, and converting it into actual cards is often a great deal
With creatures with Provoke, Morph, and Amplify abilities there's no need for spells
Out of the two D&D MTG sets, this one is the most iconic as it started it all, but overall, it is the less beloved set
Conversely, if a Hades you control is dealt lethal damage by a spell you own, the spell will be exiled, and then Hades will be exiled as well
This ability can be leveraged in a number of ways, either by building a dedicated sacrifice deck of your own, relying on enforced sacrifice effects like Grave Pact and Dictate of Erebos, or both