The use case I envision is basically this:
Suppose there's an autogen for app-editors/vim.
Suppose I add a new autogen, or add a fixed/pinned version in curated.
If I now run merge-kits, if there's a new version of vim out, it'll autogen a new ebuild for that. I don't want this at that moment. I just want to test out the changes I've made, without diverging further from upstream meta-repo.