What is Treasure Digging?

Digging is an Event brought with the Ascension Update that is essentially the same as a Great Chest and Epic Chest combined. You are awarded two free digs per day and will get prizes ranging from Dory's Soulstones and Surge Pills to Epic Weapons.

Additional "Digs" can be purchased with diamonds and at 100 Diamonds a dig are certainly cheaper than Epic chests, but the rewards aren't really super awesome.