The statusbar is an xml file similar to the toolbar xml files, and users want to be able to customize it to their needs by adding, removing and disabling features in it (e.g. bug 88296, bug 86303), so it would be good to have this feature added to the customization dialog.
I don't know if this is a good idea. On other issues I seem to remember that it's not wanted that the Statusbar is customizable.
Please consider access to macros as solution to bug 101576 that requests to show MAX(SELECTION)-MIN(SELECTION) at the status bar.
Makes sense, but not before Bug 112620 is solved, so we could filter all those toolbar/menu commands that don't apply to the status bar. (FYI sdi files used to have also a StatusBarConfig setting, but it was removed last year, because it was not used from the code - https://cgit.freedesktop.org/libreoffice/core/commit/?id=ccbed01b40c9bc4421943ebe1fe818d43aadcc7d).