If a card with harmonize is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions
A all-in commander that can protect itself can be indispensable, giving your glass cannon some much needed resiliency
The first ability is the one that Hydra decks care about, as it doubles any counters that its controller places on a permanent or player
Unlike Wizards, Vampires, and Dragons, there aren't a large number of good Cats in Magic 's history and there are barely any cards that specifically support the Cat tribe
With almost two-thirds of the deck cycling for a single mana(!), it becomes inevitable that you will draw multiple copies of this absurdly large Lightning Helix, and at this point, its hard to argue that it needs to do anything else to dominate