This has been a historically powerful concept, as it turns what might be otherwise weak equipment into actual creatures, but with the upside of leaving an equipment behind after they die
Lastly, note that "mana cost" was originally called "casting cost" up until the release of the Sixth Edition core set, which brought a number of important rules and terminology changes
Mind you, a few decks found other ways to beat it, like this second place deck: Yep, thats right, Porphyry Nodes dont target, and dont sacrifice, so they still blow up the angel
Commanders Plate Commander's Plate is probably the single best equipment for the Commander format
Okay so the Cactuar is a bit of a meme card, its true