its almost impossible for me to tell if this better or worst than git i read few things about jj, and my conclusion

   1. its different
   2. very few user would really care about this difference 

i think git is good (not good enough, good just good, or really good) and unlike shells, i cant think of a reason to have mass migration to it

people use zsh because apple choose it, and pwsh because microsoft settled on it, on linux i am sure we can do better than bash, but it good enough and nothing justified replacing it (that being said, all 3 OSes should have settled non nushell)

in summary, if we couldnt replace bash on linux, i dont think anyone can replace git, git as an scm tool if far better than bash as a shell