PCGamesN has a short article were Blizzard says the auction house is a way to secure your account from being compromised.
More information.It seems safe to say the Blizzard view Diablo 3’s auction house as a necessary evil, at least to judge from our conversation with game director Josh Mosqueira earlier today at Gamescom. But for players concerned about account security, it may be a worthwhile exchange.
“The auction house is a really complicated issue,” he said. “Like it or not our players, or some of our players, attribute real world value to the items. So [if you don’t have an] item auction house, you’re going to see a lot of account compromises.”