Cards like Nykthos Paragon can make your board state get out of control rather quickly and help end the game
Based on the latest market prices tracked on TCG Stacked, Elliptical Conflux Yellow is worth about $0.33 USD
It seems like rarity is the main force behind the price spike
Thought Monitor
[8] The common Graf Rats melds with the common Midnight Scavengers into the common Chittering Host The rare Hanweir Battlements melds with the rare Hanweir Garrison into the rare Hanweir, the Writhing Township The mythic Gisela, the Broken Blade melds with the rare Bruna, the Fading Light into the mythic Brisela, Voice of Nightmares There are a further three cards with meld in The Brothers' War : [9] The rare The Mightstone and Weakstone melds with the mythic rare Urza, Lord Protector into Urza, Planeswalker The rare Phyrexian Dragon Engine melds with the mythic rare Mishra, Claimed by Gix into Mishra, Lost to Phyrexia The rare Argoth, Sanctum of Nature melds with the mythic rare Titania, Voice of Gaea into Titania, Gaea Incarnate Icons[] Meld cards in Eldritch Moon have an icon next to their name on both the front and back faces
Some players like to speculate on card prices, so they may buy lots of a particular card when it is relatively cheap and hope to sell off at a profit later on