Maybe not for you, but there are a number of things in here that could be relevant to people's workflows. For example:

> The index file can be taught with "update-index --untracked-cache" to optionally remember already seen untracked files, in order to speed up "git status" in a working tree with tons of cruft.

There are some companies out there that are using Git at such a scale that `git status` already takes as much as 20 or 30 seconds to complete. I'm not sure if this would speed up that particular issue, but it just goes to show that Git has a large range of use cases. Not all regular git users have the same needs.