I sometimes miss useful things. For example, many years ago, I missed emerging Org Mode, not recognizing its potential, only to discover some years later how essential tool it is. And the same happened to me with EXWM, an Emacs window manager.
I’ve always thought that making a window manager in Emacs is a crazy cool idea, which is not very useful in practice. If anything bad happens to Emacs or Emacs needs to be restarted then the whole desktop goes down. It may be a good reason itself to avoid it and there is an additional question why would one use it instead of a standard well tuned window manager. I use a tiling approach to window management, with a single window displayed over the whole screen most of the time, and I don’t need much functionality from the window manager after all.
As with many Emacs tools, there is a very good reason to use it. What I missed (my fault, discarding the idea before looking at it properly) was that windows in EXWM behave similarly to regular Emacs buffers. And Emacs already has a powerful built-in window management.
I discovered EXWM because I looked for a way to easily display a web browser window (or occasionally some other application window) side by side with an Emacs frame. This is not difficult to achieve but what if I want to switch to another Emacs workspace and back? What if I want to pop up a help window instead of the web browser window and then return back to the browser? Etc. It starts to be complicated even with advanced tiling window managers like StumpWM. (And no, window manager desktops are not a solution.) While Emacs provides similar functionalities instantly with
pop-to-buffer and all the other window management facilities. When realizing this all, I couldn’t understand how I could live without EXWM. Even when not considering added bonuses, such as the possibility to use normal key bindings (compared to e.g. KDE key bindings limited to single-key bindings only and unable to use Super and Hyper modifiers).
And how about the supposed problems? Emacs usually doesn’t crash and also doesn’t block that often. In practice, there don’t seem to be real problems. Whether other applications must be restarted on Emacs restart depends on whether they are started from Emacs or outside it, which is actually not different from using other window managers.
I use Emacs / EXWM just as a replacement for the window manager, not the whole desktop environment. I keep using KDE while using EXWM instead of kwin. This means I can still use panels (with some limitations such as that it’s not possible to use autohiding panels and it’s possible to configure the panels only when EXWM is not running), general key bindings managed by KDE (useful, among other, to be able to run basic applications when Emacs is not running), KDE settings, multiple monitors (they work well without further arrangements in this environment), notifications, etc.
When setting up the EXWM environment, I realized I need a PIP (picture in picture) facility for Emacs buffers. I couldn’t find anything like this, so I wrote a simple utility called pip-frame.el implementing a floating frame displaying Emacs buffers.