As I mentioned earlier, planeswalkers are great at ending the game if left unchecked, and thats a feature, not a bug
But whereas Dark Confidant deals damage to its owner equal to that cards mana value, Twilight Prophet deals that damage to each of our opponents
That includes all the aforementioned Eldrazi decks along with Elves, Merfolk, and more
However, Phyrexian Tower can be useful in just about any black Commander deck, as it always gives you an option to trade in a creature for a quick mana boost
The 10 damage is irrelevant, but preventing your opponent from playing Item cards from their hand is almost game breakingly good
Mirkwood Bats Mirkwood Bats is a centerpiece in many token/treasure decks