For me, that's probably jj undo, just because it makes everything else so nice to just give a try. I really don't worry about making mistakes.
But for me, it's not so much features that git doesn't have, it's that the core is factored in a way that's more focused and orthogonal. The stuff that I used to like to do with git is even easier and more straightforward with jj. This is more of the result of a bunch of different design decisions and how they fit together rather than just some specific feature that's great.
Sounds like jj just simplifies the interface of some git commands, mainly. After talking to some jj enthusiasts here, I think we just have a different perspective about what needs to be simple and even what constitutes simple. There is probably some lingering unfamiliarity with git among jj enthusiasts as well. I don't want to teach git to people who are not programmers, but I wouldn't want to teach any programmer's VCS to them honestly. If you are a programmer, I think git is the best.
> There is probably some lingering unfamiliarity with git among jj enthusiasts as well.
I've heard this a few times. But from what I've seen, it seems like often it's the Git enthusiasts who seem to be unfamiliar with jj. I haven't heard from anyone who used jj for a few months and knew it well and then switched to Git.
I have never used jj, nor met anyone who used it in person. Given how new it is, you just won't find enough people who used it at all. I think git is like the vim of VCS systems and like vim there are some people who just don't think that way. I think jj might be more like emacs in that it has the initial appearance of being simple, but when you get into it more deeply you realize that it is not so simple after all.
I have used other VCS systems that made similar claims about being simpler, such as Mercurial. I think I got to be fairly expert at Mercurial before becoming expert at git, and even used it to interact with SVN repositories. (I've also used git for SVN. This is another thing git does better.) After actually learning git past the first few commands, I would never go back to Mercurial. I don't want to mix and match systems either. There are things I want git to do better, but I would not call these simple feature requests... They are more along the lines of advanced features that need to be extended or polished.
But for me, it's not so much features that git doesn't have, it's that the core is factored in a way that's more focused and orthogonal. The stuff that I used to like to do with git is even easier and more straightforward with jj. This is more of the result of a bunch of different design decisions and how they fit together rather than just some specific feature that's great.