[do_not_redeem]

I think you have it backwards. jj is absolutely for "a) Developers who want to understand their tools". The simpler data model opens up new workflows that weren't possible before.

Unifying concepts is not taking away any expressive power. It just makes the system as a whole simpler to reason about.

I think it's a similar step up in power as moving from Windows to Linux. On Windows, to toy with the system at all you need to set up a C++ project and dig through win32 API docs and deal with opening/closing handles and void* pointers just to change anything, so I rarely bothered. On Linux everything is right there in the file system so there's almost no friction to changing things. You can do anything imaginable in a minute or two with just a shell script.

In Linux, Everything Is A File. In Jujutsu, Everything Is A Commit.