I agree with Marsu and Raptor. Underused or underpowered cards aren't necessarily a bad thing, and they won't always remain so; sometimes, the meta shifts to favour those cards.
As an example, I'll use Magic: the Gathering. There was a card released back in about 1995 called 'Flash'. It was a terrible card. It let you play a creature on your opponent's turn, for basically (somewhat simplified) the same cost, and if you didn't pay, the creature just immediately died.
Nobody used the card. It was useless in tournament play. It was useless in casual play. It had no theme. It had absolutely nothing going for it. It was one of the most worthless rares in the set. If you opened a pack and got it for your rare, you swore. Then, years later, another card was printed. It was a creature called 'Protean Hulk'. It wasn't that great on its own either, though it did have some use in casual play, just by virtue of being a large creature. It was somewhat overcosted for its attack/defense (wel, power/toughness, but analogous to att/def in elements) but it had the ability that if it died, you could go search your deck for some cheap creatures and put them into play. (totaling cost <=6)
Suddenly, people remembered Flash. They used Flash on Protean Hulk. They didn't bother paying the rest of the cost; they just let it die. Then they got to search their decks for a bunch of cheap creatures and put them into play right away, on like turn 2, instead of turn 7 or more. (hulk cost 7, so would normally take at least that long, barring nova/immolation equivalents) They would pick a bunch of creatures that in combination, could instantly win the game, right then and there. Then they filled the rest of their deck with draw power, mana acceleration (Magic's equivalent of nova, upped towers, etc), and the like, to increase the odds of getting the combo.
Flash was the star of the tournament scene. People were literally building decks with TTWs of like 1.5, and nothing else could compete. Everyone used the Hulk Flash deck. They ended up putting Flash on the restricted list, which meant you could only use one of it in your deck. It was now in an elite list of a few dozen cards out of over ten thousand ingame cards as one of the most broken cards of all time.
Moral of the story; today's utter crap could be tomorrow's meta mvp.
Of course, this also doesn't preclude the fact that sometimes underpowered cards can simply be fun. Who hasn't had fun with a bone wall/schrodinger cat deck, or pandemonium voodoo dolls, or made some ridiculous trio or quartet that relies on getting a 3 or 4 card combo that only happens like 1% of the time, but when it does, it's absolutely hilarious. I once made a CATapult deck, for example, where I used auburn nymphs to buff a schrodinger's cat until it had enough hp to catapult and kill the opponent in one turn. It took something like 15 games in pvp2 before I finally got a win, but man was it awesome when it finally won :p