Could you elaborate on what
Bitcoin exchange-traded funds (ETFs) are and how they operate? Are they a direct investment in bitcoin itself, or do they involve some form of derivative? How do investors gain exposure to bitcoin's price movements through these ETFs? Do they offer the same level of liquidity and accessibility as traditional stocks and bonds? Are there any specific risks associated with investing in bitcoin ETFs that investors should be aware of? I'm curious to know more about how these financial products work and how they can be used to diversify portfolios.