It's always been a bit of a muddled issue for casual play. When I was younger and found myself in 10-person multiplayer games, someone would play Tsunami or whatever, and of course it would completely alter the field. Maybe not the most directly effective strategy, but it did help make those games dynamic and unpredictable. In tournaments, these sorts of cards are typically sideboard material. But in casual duels, there's usually no sideboarding, and a very real risk that your color hate cards will be dead weight. Cryoclasm's not a very fun card to draw when your opponent is playing a monogreen deck. One approach that is feasible, but that presents its own problems, is to figure out what kind of deck your deck might be weak to and throw in hate cards accordingly. If your deck utterly destroys most green and red decks, but loses to black decks, maybe a Karma or something would shore up that weakness. It's a dead card against the decks you're good against, and it's a lifesaver against the decks you're bad against. But it's unlikely to be that simple in casual play with a card pool as gigantic as Magic has, unless maybe you only ever play against the same few decks. There is so much diversity that no deck is universally good or bad against black (or red, or whatever). If you can't guarantee that you're going up against a particular color, and in most types of one-on-one casual games you can't, then the hate cards are, on average, much worse than other potential card choices. I've seen two other, less specific methods of implementing color hate in play that lacks sideboarding...
The first method I'll call the "All the CoPs" method. It involves using several different hate cards in the same deck. Some of them will be dead, but some of them won't. The idea is that with the right balance, you'll always have something to cripple your opponent. It was probably sort of the idea behind the design of the Urza's Saga "Rune of Protection" cards. The original Circle of Protection cards were widely considered, except in a few exceptional scenarios, bad cards because they were too likely to end up being dead weight. The Rune versions of the cards were similar (they required white mana instead of generic mana, which wouldn't be a problem in most white decks), but with Cycling 2, meaning that Runes for the wrong colors could be cycled for fresh draws. So not only could you be sure to have your hate card for whatever color your opponent turned out to use, but the other ones you drew could be converted into new draws rather than being total dead weight. And you know what? The Rune of Protection cards were (and are) considered crap. There was another card, printed not much later, that was put to much more use: Story Circle.
The second method I'll call the "ReapLace" method (after the obscure Reap/Deathlace combo that sort of relies on the same principle). It involves some means of ensuring that your hate card won't be dead weight. The best example of this method I can remember is a Douse/Mind Bend interaction (maybe I should call this the "DouseBend" method? Nah). If I'm playing a blue deck and my opponent is playing a red deck, Douse is a pretty strong card. If my opponent isn't playing red, well, Douse is dead weight. But if I'm also playing Mind Bend, that's no longer the case, because my opponent is probably using some spells and those spells probably have some color. The combo loses some of its punch against artifact-heavy decks and against decks with lots of colors, but the principle is still there. A card that might theoretically be dead against most opponents can be made pretty powerful if it's combined with something else. This method has some potential, but since it requires a second card for one of your cards to do anything reliably, the hate card had better be really powerful, so powerful that you're willing to take the risk.
