If you work on a small code base, or if you know the code base perfectly, you might get away with your "tried and true method" most of the time.

But if you are working on a code base with hundreds of commits per month, I wish you a lot of luck. Your 10s of seconds might easily become days.

On a big codebase you might even want to automate bisecting as much as possible. See http://lwn.net/Articles/317154/ where Ingo Molnar says:

>>> for example git-bisect was godsent. I remember that years ago bisection of a bug was a very [laborious] task so that it was only used as a final, last-ditch approach for really nasty bugs. Today we can [autonomously] bisect build bugs via a simple shell command around "git-bisect run", without any human interaction!