Last Friday a code check-in was made that made Jira functional tests fail only in Standard and Professional editions.
If it was not for Bamboo, we would not have picked that up until midnight on Friday (for a while we have had a nightly build that does a lot of automated testing). Which means that it would not have been fixed until Monday, and as the author of the change is off on holidays for the next 3 weeks, some one else would have had to get clued in on why the build failed, before they fixed it.
Luckily, not too long ago, we have configured Bamboo to run tests for all Jira Editions after every check-in.
Overall, I think Bamboo just saved us at least 3 hours of precious dev time.

Bamboo Saves Jira a Headache