[arxanas]

It's certainly true that jj's features won't appeal to everyone. I think a lot of its features are quality-of-life features (consistent commands and concepts, general undo), and a lot of its features don't help a certain class of users (flexible commit rewriting/rebasing), so it's not surprising that some seasoned Git users won't find it that helpful.

I think it's unfair to call it a "thin UI layer". My own project git-branchless https://github.com/arxanas/git-branchless might more legitimately be called a "thin UI layer", since it really is a wrapper around Git.

jj involves features like first-class conflicts, which are actually fairly hard to backport to Git in a useful way. But the presence of first-class conflicts also converts certain workflows from "untenable" to "usable".

Another comment also points out that it was originally a side-project, rather than a top-down Google mandate.