>>95907959
>doesn't do shit unlike Thoughtseize
Grief is just Unmask in creature form which is still legal in Legacy, Vintage, and premodern. By removing a black card from your hand from the game, you can force your opponent to discard a non-land card of your choice without paying mana. It does the exact same thing as thoughtsieze by itself only just by removing a card in your hand from the game instead of having to tap a land which makes it a strong card in spite of its drawback. Or you just wait until turn 4 to play it and have it do the same thing as thoughtsieze.

The reason Grief was banned is because there is a surplus of one mana cost cards for black that all you to return a creature to play when it dies after entering play as per the revoke cost like undying evil which allowed you to remove TWO cards from your opponents hand of your choice and then get a 4/3 on turn one. Yeah you could bolt or swords it, but do you really have any of those left in your hand after this thing came into play twice? THAT is why it's banned. Not because you can look at your opponents hand and remove one card.