Because there are substitutions in the command such as current file, and the directory that the command runs in can also be a substitution, showing the actual command thats run and where its run is useful. Its shown I ran a command on the wrong file many times
It seems like that's duplicating what `make`, `ninja` and similar tools already do though, in addition to also confusing what the "Compiler" tab contains; not just compile/build output as described in the manual, but also some non-build status messages generated by Geany.
In any case, IMO the simplest solution, as previously mentioned, would be to add a new menu item to the context menu of the Compiler tab to allow copying only the _actual_ build output, and none of Geany's injected status messages. This way doesn't require adding any preferences or removing existing functionality or such.