It's too close to the Springjack Pasture without adding a whole lot of quality to the deck.
Sun Titan also requires as much, if not more building around than Primal Titan and is just a bit clumsy to get very excited about
Dont forget that there is a real opportunity cost to every hour you spend flipping through Icatian Javelineers, and grinding out every last nickel is usually inadvisable
And it seems the community may be on my side here because, on the secondary market, Mega Hyper Rare cards are currently plummeting in price
For example, if you dont have a second land, you want to discard something from hand, or the opponent has a graveyard hate ready
Untapping and goading the attacking creatures won't remove them from combat, even if they're attacking you