This 3 damage is exactly why Tarnished Citadel is so useful in Darien EDH decks. The Legendary Soldier’s ability creates a 1/1 Soldier token for each point of damage that you take. This means each time you tap the Tarnished Citadel, while you take the damage, you benefit with three new pawns for your army. This seems like a fair tradeoff, since Darien has ways to regain that life in his arsenal, such as the reliable Clerics Soul Warden and Soul’s Attendant.
From a low of $1.50 in December of 2015, the Citadel has been on a slow, steady rise towards $2.00 realized in June of 2017. But since that time, the price has fluctuated rather noticeably, continuing on an upward trend. While it has not yet reached the nearly $6 price tag that it enjoyed back in 2012, Tarnished Citadel is not a card that would be expected to see a reprint any time soon. While it’s not impossible that this card could enjoy a future reprint, it;’s more likely that this Odyssey rare will become an increasing rarity.
Since there is a slow and steady demand for this card from players of the EDH format, it isn’t at all unlikely that Tarnished Citadel may once again be a card worthy of being valued around $5. While the only way to prevent the effect damage from Tarnished Citadel reliably is something like Rune of Protection: Lands (yeah, that is a thing), 3 life is a small price to pay for reliable mana fixing. This Odyssey land, then, is worth adding to your collection, even if only to make “easy money” in the long run.
(2018 Update: In early March of 2018, Tarnished Citadel now lists for about $3.50, but the TCGPlayer Market Price sits just north of $4. This card is definitely worth the investment!)