alt Hacker NewsGit already won through Github, the Linux kernel, and other important projects. Even if you like Mercurial's syntax better (I do) and wish it won (I do), that battle was over many years ago.
jj's data store is git. You can use jj while other people on your project just use git. There's no migration of data or history. You can use Github and all of the various git tooling that exists today.
As such, the initial cost of switching to jj is zero for individuals, teams, or projects. That's huge.
jj's ergonomics are significantly nicer. Fewer ways to shoot yourself in the foot, much better merge resolution, etc.
It is possible to move one step further: use own store, speak git protocol. In the end, it is about the commit-tree-blob model. I think, the main headwind is the broad decay of interest in computer science topics.
Where can I read on jj merge resolution strategies? LLM links to Arch Linux man page and other random stuff.