Its nothing game-breaking, of course, but this card would have been plenty strong if it transformed into a regular ole Plains, so this makes it even better
With all sorts of ways to reanimate and regenerate him with other Zombie-related cards, you can maximize Thraximundar's power turn after turn without dropping momentum
Urza, Lord High Artificer on the other hand, frequently sees play in the command zone, and I think his salt is almost entirely due to how easily breaks the symmetry of cards like Winter Orb and Static Orb
He noted that there was a gap, as only the colors were covered, so Jules volunteered to monitor the colorless cards, most often artifacts and landsbut we did have some sets with Eldrazi coming up at the time
This, however, is not the main reason the card is so expensive
Repeat as needed bonus points for using Seedborn Muse to aid and abet