I can't believe no one mentioned this, but: remote access.
I spend most of my day connected to machines via SSH and yazi offers a great UX with file previews and all. Using kitty I even get image previews in the terminal.
To be fair, X11 forwarding is a straightforward thing, bearing in mind any security/performance/administrative restrictions which may apply to your situation.
Alternatively, SSHFS can be used to mount a remote directory locally.
I can navigate without using my mouse. It's faster for me. You can create tabs, copy and paste files, extract compressed files, run commands, and so much more without lofting my hand. My favorite feature is the ability to preview files without even opening them. I'm relatively new to linux too.
Download 5 seasons of some show from multiple sources or some artist's entire discography, and want to normalize all the file names? It is way easier in the terminal.
I'll check this out, but I use https://github.com/stevearc/oil.nvim for such tasks as I have nvim's full suite of editor commands to rename all the files way faster than I could in a GUI. I'm sure there are GUI apps to perform a similar task, but I already know how to use nvim.
Terminal file manager are useful on a server over ssh.
ripgrep and fd support is better than any GUI file manager find and replace.
Some people like using vim keybindings
The three panel view is really useful. On the left is the parent folder, the middle the current and on the right a preview, e.g. the selected folder or the contents of a picture or a text file. It's faster to navigate and pop back into the shell.
You can probably do some more advance tasks via CLI. Also usually lists information faster. But honestly you will be overall fine with GUI a majority of the time.
Other people have given great reasons, but I will also mention that as someone who lives inside the terminal it's often faster and easier to open it right there rather than getting a GUI one going. I do still use one for things that are easier to do with a graphical file manager though, no problem having both
I wouldn't bother unless you find yourself doing more through the terminal than through GUIs.
I don't have a built-in file browser (not using a DE, just i3 window manager), so I use ranger and pure GNU coreutils commands mostly but I still find myself missing the drag-and-drop features that FreeDesktop integration provides for stuff like nautilus.