An europan friend say me that the South Israel/Negev/Edom is "less Holy" for Judaism than Judea and Samaria, is this true?

Basically i was talking with this friend about bronze age states in a test about history, and he say me that the ancient kingdom of israel cover only central and north Israel, west bank/judea-samaria and the eastern jordan river valley, and the inclusion of edom/south israel in modern israel was more for 20 century history than for being very important, is this true or my friend was trolling me?