Grixis is known for its removal spells, card draw, and mighty planeswalkers, but with creatures getting more and more powerful with every new MTG set, even this control and spell-heavy color combination gets fearsome creatures
And, as with any card that doubles, Prodigy does have combo potential, though with how complex it can be to set these combos up, you might be better off just relying on the raw power of doubling specific abilities: 1
If you are building for the game against a mill deck, you've sacrificed the efficiency of your deck against every other match
Since Urborg, Tomb of Yawgmoth makes all lands into Swamps, so long as someone at the table has a copy in play, you can recur Bubbling Muck and untap lands as often as your cards will allow before casting a spell like Exsanguinate or Torment of Hailfire to win
Only your opponents may activate this ability
Since these sets were printed in small numbers, players had been able to boast about their collection, and it really was impressive if you managed to get a hold of a decent chunk of these sets