Most likely highlighting my ignorance here, but would a more obvious answer be that the earth terminal is just there to ‘park’ the cpc where a light fitting is changed but is using the existing wiring from a fitting which previously utilized it?

Most likely highlighting my ignorance here, but would a more obvious answer be that the earth terminal is just there to ‘park’ the cpc where a light fitting is changed but is using the existing wiring from a fitting which previously utilized it?