You can but they want to see the “Local” view from the perspective of other instances. If you go to your homepage a click the “Local” button at the top you see only posts from sh.itjust.works communities. OP is on lemmy.world so they see just lemmy.world communities if they select that option. They want to see this page from the perspective of any instance they want.

Could be useful particularly for instances that are topic-specific, instead of general purpose.