amen!
really, do people even use git bisect? If you do, you go through some rite of passage and I've seen people including myself make better (not perfect) commits. It remains a black art to gauge what the perfect amount of work in a commit should be.
Eh. Not really. A clean history is a good resource for figuring out what was changed and why. Cleaning up history isn't even that much work anyway.
> When you're digging through VCS history due to a bug you often ignore the commit message anyway - if the code did what it seemed to do you wouldn't be there.
Only if the commit messages are shitty, which unfortunately they often are. I try to summarize what I'm changing and what I indent those changes to accomplish, because if there's one thing I hate doing, it's spending more time than necessary to puzzle out what I (or a coworker) was thinking at the time.
VCS history can be a pretty powerful tool, but a messy history discourages the use of it.