Tom Lee predicts that if a Bitcoin spot ETF is approved outside the US, Bitcoin could surge to $150,000 or even $180,000.Lee believes the approval of a spot ETF would unlock massive demand from institutional investors and contribute to a strong price rally.Growing cash reserves and potential market re-entry point to future growth and stability in the crypto market.Tom Lee highlights the potential of international markets, including China, for diversifying portfolios amid domestic volatility.