It's a simple wrapper for X11 functions that allows for the user to interface primarily with Emacs.
It features workspaces, multimonitor support, i3-like keybindings, and works practically out of the box!
It'll manage your external programs in native Emacs buffers as well.
Unfortunately, as a result of the browser oligopoly, it's not feasible to access many resources on the internet without a modern browser, so I'm making use of a Firefox compatibility layer to allow for the use of Firefox's keybindings through Emacs.
My configuration can be found here.
Thankfully, even if I'm not using EXWM, Emacs just displays an error that 'another X window manager is running' when the EXWM configuration is loaded. It's no problem to keep the configuration in my dotfiles even when I'm using bspwm or another window manager.
As I make more extensive use of org-mode, I find myself using fewer and fewer tools outside of Emacs. I've found that the tools I do use often have Emacs plugins that allow them to be used as Emacs functions as well.
Really, Emacs (and EXWM) are partial solutions to a more systemic issue -- the way in which the Unix philosophy has lost its way on the modern Linux system.