In the case of Affinity and Burn, they also punish Abzan for its internal lifeloss due to Thoughtseize, shocklands, and fetchlands
On top of directly affecting your first three turns, Sphinx could also let you run a more spell dense deck by cheating on lands
Artifact Ramp (CTRL to add secondary) Removal Oko, Thief of Crowns +2: Create a Food token
Red doesn't have the best interaction around, so this card can cover some of its weaknesses by offering utility beyond simply smashing an artifact
So what tends to happen is that eager beavers will trade for a couple of pieces from some exciting new deck (generally right after they see it perform well on stream and the prices are at their highest) only to give up once they realize, holy mackerel, Vengevine is itself a $50 card and Leyline of the Void is up to $60 and you need a playset of Arid Mesa and wait, how much is Blackcleave Cliffs these days