This three-ink card has a strong effect when it comes into play, one that is pretty unique even now
The reason that the card costs so much is that it is pretty much the number one most iconic creature from Magic during that time, with Serra Angel an easy choice for second place
The first is that it enters the battlefield untapped, letting you use it right away, such that it only costs a virtual one mana to deploy provided you can make use of the mana it provides immediately
Making lots of money on the collectable side is fine, but there comes with it a responsibility to reinvest in the core parts of the actual game the collectable is based on
And when it happens, some games will end after you turn one enabler into turn two Cathartic Reunion or Ox of Agonas into a lot of power
The ability also triggers if our opponent targets it with a spell, which makes it somewhat resilient to removal