A resposta para sua pergunta é que nem todos os itens nessa caverna lhe trazem a maldição. Apenas as moedas fazem, como explicado a Elizabeth pelo capitão Barbossa:
You don't know what this is, do you?
It's a pirate medallion. This is Aztec gold. One of 882 identical pieces they delivered in a stone chest to Cortes himself. Blood money paid to stem the slaughter he wreaked upon them with his armies.
But the greed of Cortes was insatiable. So, the heathen gods placed upon the gold a terrible curse. Any mortal that removes but a single piece from that stone chest shall be punished for eternity.