While the flexibility these abilities offer is already quite powerful, unlike other Planeswalkers that may only activate one ability per turn, you can instead activate two of Urza's abilities during each of your turns
If an opponent tries to remove it, the presence of its Ward - Pay 7 Life ability will essentially give it an eighth keyword: haste, and attacking into it is almost impossible to do profitably
Modern Horizons 3 [Best for Competitive Players] Modern Horizons 3 is the kind of set that grabbed my attention right away
Lightning Bolt is arguably the most perfect card ever designed
Fanatical Devotion 6/10 Martyr's Cause 5/10 Both three mana enchantments that give you some protective utility and the holy trinity of sacrifice potency
Blue is often added for its many cantrips, defensive counterspells, and hyper-efficient draw like Windfall or Echo of Eons