Pre-commit hooks are not possible [yet?], which is a minor inconvenience. Worse, workspaces/worktrees use a different mechanism. This causes like Claude Desktop (which uses worktrees) to break. Also Claude and other agents are always confused about JJ and fall back to git too often.
Can't be easy to build a GUI on top, but I'm sure a 10% revenue to be redistributed to the hero behind jj would go a long way. Would also pay off.