On Linux this functionality is usually provided by GVFS or KIO. But if you have authenticated to a network resource under Dolphin (KIO), you can't necessarily edit a file using a GTK+-based editor - or even a Qt one that isn't KIO-aware. I think GVFS has the better design: falling back to symlinks is just less surprising for mixed applications (e.g. can't open a terminal on a KIO smb:// directory) even if you can't map everything perfectly to POSIX semantics.