Also, after some testing, it turns out that my previous assumption about
systemd was wrong. Placing a service in default.target.wants directly
will cause the service to instead not be recognized by systemd.
The desktop directory is used for desktop-related things that may be
useful outside of bspwm (such as caps lock functioning as ctrl +
escape). Whether or not this is needed is questionable, but it is an
option for now.
It may be better to further split these directories and avoid the
generic word "desktop" altogether.