the only difference is that you get to cast instants basically at any point in the game
Cheap burn is super important so that you can keep up the tempo, applying pressure and removing things all at the same time
Lasting Tarfire is a two mana enchantment that deals two damage to the opponent during your end step if you put a counter on any creatures during your turn
Having both Vigilance and Menace makes her a real pain in combat, and it means that, despite her high casting cost, she can come in and usually connect without much trouble (especially if she hoovers up a haste-enabler)
Oh hey, its another way to make treasures in green
Presale prices for each of the Elder Dragons is as follows: Witherbloom, the Balancer: $34 Prismari, the Inspiration: $29 Lorehold, the Historian: $27 Quandrix, the Proof: $24 Silverquill, the Disputant: $22 Opening one of these mythic rare Elder Dragons will cover the cost of a few play boosters, especially if you cash them in at your (pre)release event