TLDR PT (points) = thickness
Both are valuable, but its the Lorcana Enchanted Rare Discard card that is worth the most, being finished with the holographic inkwash treatment usually reserved for Lorcanas rare Enchanted cards
If you control a Vampire, each opponent loses 2 life and you gain 2 life
Like most Magic: The Gathering cards, the value of Plains depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (The Brothers' War)
(Must have a partner to play) The team does not share any other resources other than life
It's not quite as effective of a finisher as something like Moonshaker Cavalry at the same cost, and there are fewer ways to search it up or get it back from your graveyard, but it's also a third of the price in paper