We have a handful of lands like Promising Vein and Shire Terrace that sacrifice themselves to find a basic Wastes to get a land into our graveyard, and there are a slew of lands that can give us additional utility from our manabase: Inventors Fair can help find a key artifact, Buried Ruin can recur something from our graveyard if needed, Demolition Field can destroy a pesky Glacial Chasm or opposing Field of the Dead, and Lazotep Quarry even acts as a reanimation spell on a land
If you pair Emerald with Steel, you can even gain access to the infamous Grab Your Sword and A Whole New World
Given how long Celebrations has been out by now, and the fact that a reprint is unlikely, I doubt this value will go down much in the near future
Exploration 3 Very powerful but unfortunately not well placed
However, the increase value is also low, and if it is activated only once or twice, it will easily be defeated in battle
The reason we don't see loads of this getting play is that it only works brilliantly in the Sneak based deck