Dired stands for directory editing.
One of my favourite features of Dired is the ability to mark or unmark multiple files in a variety of ways: manually, using repetition counts, or with regular expressions. This can be done fluidly and spontaneously as we browse and inspect files. Once we're satisfied with our selection, we can perform bulk operations on them such as copying, moving, deleting, changing permission bits, compressing the marked files, etc.
It's a bit like how we can use a GUI desktop environment to mark multiple files and then perform bulk operations on them. This is something we cannot easily do on the shell with the standard Unix utilities. But we can do all of this from within Emacs using very concise sequence of keystrokes and muscle memory.
Further, unlike most GUI desktop environments, every Dired interaction is scriptable, recordable, and replayable. I mean every operation or key sequence in Dired is available as an Elisp function, so we can script repetitive tasks by writing small Elisp snippets. Or, alternatively, we can have Emacs record the repetitive actions as keyboard macros, which we can then replay as many times as needed. I no longer have to worry whether the underlying GUI desktop environment supports these features or not because I know Emacs does and I can just use Emacs to browse my system.
And that brings me to another important benefit of using Dired: my muscle memory for Dired is transferable across a wide variety of systems and environments. It doesn't matter whether I'm working locally or logged into a remote shell, or whether I'm on macOS, Xfce4, KDE, etc. I can browse and edit my files and directories in exactly the same way using the same muscle memory and the same set of Dired commands, key sequences, and features!
A couple of years ago, I used to host Emacs book club meetings. I've kept some notes on directory editing with Dired from those sessions here: <https://susam.net/cc/mastering-emacs/ch06.html#dired>.