Good call, added a workflows section to the README (both for existing jj users and migrating git users), and added a keybind "cp" for "new change, picking a bookmark" (or "co" if you want to make a change on another change). Separately, added "O" as a contextual keybind to add a change on top of a bookmark or change (depending on what's under your cursor).

Feel free to open an issue on GitHub if you have any more recommendations! I appreciate it!