Desire All for Thy Belly
To play this card, you must discard a Spawn card from your hand. Reveal to yourself a number of cards from the top of opponent's play deck equal to the number of Spawn cards in play. Eliminated Spawn do not count. Choose one card and show it to your opponent. He must choose to either: remove the card from the game or decrease the number of cards he may hold in his hand by one for the rest of the game. Shuffle and replace all remaining cards back on top of his play deck. Remove this card from the game.

Out-of-play Pile - Your cards that are removed from play after being used and that do not award marshalling points are placed in your out-of-play pile.

Note: If a unique card is eliminated, that card may not be brought back into play by either player.

Ale, jeszcze zakładając na chwilę, że "removed from play" i "removed from game" to jednak to samo.
Co w sytuacji, gdy postacią, o którą chodzi jest Aragorn II (bo to mnie akurat konkretnie interesuje) ? Jeśli leci do out-of-play pile'a, to, ok, jest w grze przy rozpatrywaniu unikalności, ale czy osoba zagrywająca DAfTB dostaje za niego 3 MP ?

-to "after being used" nie traktowałbym jako warunku trafiania do Out of play pile

To rozróżnienie play-game w kontekście unikalności ma sens, tylko zdaje się nie jest to rozróżnienie akceptowane.
Prosty przykład News of Doom: czy przeciwnik może zagrać tą kartę po usunięciu jej z gry przez ciebie?

W przepisach faktycznie słowa game i play są używane przez ICE swobodnie

W Dragons jest mowa o eliminacji manifestacji smoka, lub innym sposobie usunięcia jej "from game". Tak jakby eliminacja była formą usunięcia "from game". W tym samym rozdziale wyjaśnione jest to na przykładzie, gdzie Smaug i jego manifestacje są usuwane "from play".

Only your opponent can receive marshalling points from defeating a manifestation of a Dragon that you played. If you defeat a Dragon manifestation that you played, it is removed from the game and no one receives its marshalling points. If at any time an attack from a manifestation of a unique Dragon is defeated or if the manifestation is otherwise removed from the game:
• All existing manifestations in play of the same Dragon are removed from the game.
• No further manifestations of the same Dragon may be played.
• The Dragon’s lair no longer has an automatic-attack.

Example: You have played Smaug at Home and Smaug Ahunt (both are still in play). Then you play Dragon’s Desolation and Smaug on one of your opponent’s companies at Weathertop. Your opponent plays Old Thrush, rolls lucky, and defeats Smaug. He gets 5 MPs for defeating Smaug and Smaug, Smaug at Home, and Smaug Ahunt are all removed from play and The Lonely Mountain (Smaug’s lair) no longer has an automatic-attack.
If, instead, one of your own companies had gone to The Lonely Mountain and defeated Smaug at Home, you would not receive the 5 MPs.

Different manifestations of the same Dragon may be in play at the same time. The fact that each manifestation is unique unto itself does not preclude the other manifestations.

Z kolei w Balrogu mowa o tym, że przeciwnik Balroga może usunąć "from play" posiadaną na ręce manifestację Balroga.
Co wtedy, kiedy Balrog jest już w grze, albo jedna z jego manifestacje już leży w out-of-play pile?

If you are a Balrog player, your opponent may not play any of the following cards: The Balrog (Ally), The Black Council, Durin’s Bane, Balrog of Moria, Reluctant Final Parting.
However, if at any time your opponent has one of these cards in his hand, he may remove it from play and bring one card from his sideboard into his play deck.