What are the negative consequences of setting `feature.manyFiles` for small to mid-size repositories?

Question

git provides a feature.manyFiles option that intends to make experiences in large repository smooth. What would be the consequences of turning it on also for small to mid-size repositories, such as:

git config --global feature.manyFiles true

Answer 1

I mentioned this option in Git 2.24 (Q1 2019).
And, as I noted here, that option would not change much on MacOS.

That option was originally discussed here, and also here; after this 2019 discussion.

The feature.manyFiles setting is suitable for repos with many files in the working directory.
By setting index.version=4 and core.untrackedCache=true, commands such as 'git status' should improve.

It should not impact small to medium repositories (since they are small-er, the optimization extra work won't be a big enough factor to be noticeable)
And it will improve git status for larger repositories.