- power user workflows may differ from typical dev workflows. Imagine things that a point-and-click file manager solves quicker than the command-line. Example: manually organizing a bunch of .mp3s, or cleaning out misc downloads. A TUI file manager makes these tasks quicker too.
- quick directory navigation. cd is slow. There's solutions for a better cd, involving z or fzf or whatever. But a file manager should solve it too.
- a file manager, especially a two-pane view, is cognitively easier. Better UX. Example: Having a src/ pane on one side and dst/ on the other, selecting a few src/ files, then performing a copy command. You get instant visual feedback to confirm that the files appeared in dst/. Compared to ls, cp file1 file2 file3 dst/, ls dst/. I always feel the need to ls after commands because the command-line doesn't give much feedback.
tldr: speed, ux, comfort. But if you're already comfortable with your tools, I think that's the most important thing.