Some reports estimate the collectibles market will cross $10 billion+ globally by 2027, with trading cards being one of the fastest-growing segments
People want almost every single card from the set
These only produce the color combinations associated with the factions in Khans of Tarkir (one color and its two enemies), but Hour of Devastation also gave us Crypt of the Eternals, which can filter mana into blue, black, or red (the colors of Nicol Bolas)
All of that is great, but back then there were answer cards like Swords to Plowshares that could render that moot and stick you with a rather annoying bill
In the best-case scenario, you could add a counter on up to four creatures on your side of the battlefield while also saving your mana to cast other spells
It may not look like much upfront a 3/4 lifelink creature for four mana is hardly earthshattering but it offers black decks something they dont otherwise have in Standard: a way to get some of that lost life back