In a statement released to Kotaku, Blizzard Entertainment explains why it decided to lock down digital purchases of Diablo III for 72 hours. The sum of its statement is that all of this was done after the most recent patch to ensure that the game and the auction houses are not compromised and remain pure. The company also added the delay to stop hucksters and fraudsters from perpetrating credit card fraud schemes.
While Blizzard intended the delay to thoroughly check purchases, the company said in its statement that it didn't intend for the wait to be so long or for there to be a level cap. This was caused by a bug in the new patch, which they are fixing.
The statement also lists a number of "standard security-related restrictions" that will be in place for digital purchases until the payment verification process is complete:
• No public game access for unverified digital purchasers
• No auction house access (real-money or gold) for unverified digital purchasers
• Unverified digital purchasers cannot trade items or drop items for other players to receive
• Unverified digital purchasers are not able to chat in any public or game channels
• Unverified digital purchasers cannot attach a custom message to friend requests, but they can send/accept friend requests, and play with their friends
• Global Play is not available for unverified digital purchasers
You can read the entire statement here. Blizzard emphasizes that the verification process takes less than a day to complete in most cases and this long delay is only temporary...
Source: Kotaku. Thanks to Andrew Eisen for the tip.