Each player, starting with you, separates all of his/her permanents into three piles. Then, each player chooses a pile at random, and sacrifices all of the permanents in that pile. It’s an interesting sort of Russian Roulette. Why anyone would play this card outside of perhaps Commander (where there are plenty of ways to abuse a card like this and get all of the permanents you lost back anyway) is beyond me.
But wait, there is an interesting caveat to this card. There can be empty piles. Yes! This means you can actually separate cards into two piles, and randomly pick a blank one OR put all of your eggs in one basket and pray you don’t randomly hit the one with all of the permanents. Talk about a crazy card.
So, there are possibly ways that you could play this card and cripple your opponent without losing a thing. Essentially, you are trying to cheat fate. Just from a flavor perspective, this card wins big time. There are Commander players out there that will find a way to make this land crippling blows while escaping the worst of it with cards like Second Sunrise and Faith’s Reward that let them get the cards they lost back anyway.
As far as Limited is concerned, just hope that you never run up against Whims of the Fates. It will happen. If you get passed this card with nothing else you can use, take it just so someone else doesn’t use it against you. You’ll feel a lot better knowing that you didn’t let this get you, and it’s completely splash-able and possibly crippling at only 5R (5 colorless, one Red).
I'm sure that Wizards created this card to be one of those Limited nightmares. As soon as you see a Mountain, you never know if this card is coming to try and force a comeback or the always dreaded draw…
Really, though, it's just a fun casual card, and perfect for those players who love to dedicate their decks to create more than a little bit of chaos.