Presumably you also put more time and focus into emails that are being sent to 1,100 recipients versus emails to 1 recipient, and you send more of the latter than you do the former. But the "undo send" gives you 10 minutes of extra-edit time to that important announcement as well as every other email you send.
If "undo send" gives a psych boost to being obsessive-compulsive, this still doesn't address the additional layer of possible failure. You have better control over your ability to not hit "Send" then you do to do a panic cancel as you do a last second proofread.