Sacrifice has its purposes but can also be easily navigated around by your opponent with tokens and cheap creatures
Mox Sapphire ($4,666) Blue is, and possibly always has been, the most powerful color in Magic, so its no surprise that Mox Sapphire is the most expensive of the cycle
There's a lot of charm and quirks from the other games that have a high potential of being miss (WotC please make Sabin suplexing Phantom Train a card)
But, having Adrix and Nev, Twincasters as your commander makes it so you have a reliable token doubling effect always available to you, provided you have the mana to cast them
"Reuniting Pioneering Artists of Magic"
Even in weaker builds of Urza, the deck snowballs very quickly and can cast a ton of spells without ever really trying