What is one drawback regarding bitcoin ETFs?

Could you elaborate on the potential drawbacks associated with investing in Bitcoin ETFs? I've heard that while they offer exposure to the digital asset class, there may be some concerns investors should be aware of. For instance, do they face regulatory hurdles or liquidity issues? Additionally, how do they manage the volatility inherent in Bitcoin, and could this impact their overall performance? Clarifying these aspects would help investors make more informed decisions.