Personally I think that was a mistake. If someone can't be bothered to keep her computer's clock set right, then kick her off the network.
And in a decentralized system with no central authority to provide a time server that everyone must synchronize with, who gets to decide which timestamp is "right"?
The blockchain provides sequencing in the absence of a reliable source of synchronized time. Transactions in more recently added blocks "always" occur after transactions in less recently added blocks, regardless of what "time" they happened.