A lot of GUIs have less options available than their CLI equivalents. Moreover GUIs change more often, requiring you to relearn the actions to get the expected result Shells can remember the commands you used, commands are also way easier to write down on paper than a list of actions to do on a GUI And using man or --help is not going somewhere to know the options, you stay in the shell If you want to know all the features of a tool, reading the manual is also easier than browsing all the GUI
The CLI lets the user automate tasks, giving them more control over their workflow
I tried to switch from plex to jellyfin 2 months ago, running both at the same time in containers, but I removed jellyfin after a week
The main issue was the CPU usage, on idle Jellyfin was using about 1vcore while plex used only 0.3, no background tasks seemed to be running and after a week my 4tb of media should have been indexed
Also a feature that I use regularly with plexamp, starting a radio from a song, was not giving me good results on finamp