- Ease of integration enabled parallel development.
- Smallness of commits meant easy bug isolation.
Because of the ease of integrating small commits, my coding companion and I were able to develop two complementary sets of changes in parallel. This saved us quite a bit of time because we didn't have to wait for each other. The changes were developed as a last-minute response to a problem right before release, and without the ease of integration, it would have been hard to get the problem right on a compressed schedule.
Small Commits => Easy Bug Isolation
Also, because commits are so small (because it's easy to commit without any side-effects, because your repo is isolated from everything else), it was easy to isolate the exact changes that caused a subtle problem. I could have used bisect, but I had an inkling which change caused it, so that was faster. With svn or a mongo patch accrued over multiple changes, it would have been much more confusing and disorienting.