Depends on the level of risk tolerance you have, I suppose. With no confirmations, it seems pretty easy to rip you off. With just one, there are attacks that could let you see a false confirmation. With two, it's getting a lot more difficult, but something (not even necessarily a heist) could conceivably break the network itself.
I couldn't articulate the reasons better than they have been, but there were good reasons right before SwC went to two that they did.
But don't other sites like Primedice accept 1 confirmation, and also process withdrawls if there has been only 1 confirmation.
If it was a big issues wouldn't they be moving to more than 1 as well?