Joanna Rothman notes the following benefits of continuous integration:

• Continuous integration provides early feedback to developers.
• The PM can see every day if the build is broken. (I use this as a predictive metric.)
• There's less to check in every day, so it's easier to see where the problems that broke the build occurred.
• It's much more obvious earlier whether we have enough tests to know if the build is any good.

and asks us if we have more to add.

For myself I'd note the following:

• Developer morale benefits from knowing that there isn't an invisible mountain looming up in front of you

• Those who mess things up are forced immediately to switch their efforts to undoing their evil, which (hopefully) means they can't be busy digging a deeper hole
• Developer morale benefits from knowing that if you are the one to screw up, the scope of your crime will be small enough that no-one will actually hate you for it (unless you screw up a lot)
• If you screw up a lot - there's no-where to hide. Developer morale benefits again.