there are benefits to having vices, thats not to say there a great thing from a moral perspective. greed for example has the most obvious practical benefits. in contrast, being moral can lead to harming yourself, altruism is a virtue, but it can also lead to you being a doormat for everyone else. morally great, but practically not great.
the intent of the series is that there are vices and they have effects that relate to the vice named. some vices are powerful by definition, wrath for example. if vices were only able to be inflicted on the opponent, what would the card be? "your opponents weapon swings with rage and does 5 more damage to you each turn"? since its a vice, it cant empower you, but wrath doesnt have any immediately connective negative side effects, aside from being morally wrong.
some vices just dont lend themselves to debuffs, but rather should be buffs from a practical standpoint.
wrath /ræθ, rɑθ or, especially Brit., rɔθ/ Show Spelled[rath, rahth or, especially Brit., rawth] Show IPA
–noun
1. strong, stern, or fierce anger; deeply resentful indignation; ire.
2. vengeance or punishment as the consequence of anger.
I would make this an ability that increases attack power at the cost of lfe or quanta forced on the opponent. Wrath or Violence is unreasonable and unjustified and the action behind it costs the user of wrath more than the gain. This is why it is a Vice.
al·tru·ism /ˈæltruˌɪzəm/ Show Spelled[al-troo-iz-uhm] Show IPA
–noun
1. the principle or practice of unselfish concern for or devotion to the welfare of others ( opposed to egoism).
When used as a Virtue is to put the welfare of others before your own. The net gain is that support of a group will be more effective than a single entity in the same situation. Ie Tank for the Medic and archer and the overall effectiveness is increased.
Virtues improve the overall gain and because of this are consider morally good. Vices are a loss or burden and as such are morally wrong. Some things are subjective, like survival of the fittest. Choosing to eliminate components is considered morraly wrong, but supporting the components that will have the longest projected benefit is morally right, but both are aspects of survival of the fittest.