I like the idea of conventional commits, but the lack of many useful categories is a real `chore:` to where I end up making my own, which tooling of course doesn’t recognize. The codification of something called conventional commits strikes me as kind of counterintuitive anyway.

> Is adding them manually to the commit message functionally equivalent to using the `--trailer` flag?

Yes. The flag is perfect for scripts but it's exactly equivalent to adding the text manually.