Gold bull Peter Schiff on Tuesday raised concerns about limitations in trading Bitcoin (CRYPTO: BTC) through an ETF. What Happened: Schiff explains in a post on X that these funds are only tradable during U.S. market hours. According to him, this timing can become an issue if the Bitcoin market dips overnight, leaving investors unable to sell until the next trading day. “One problem with owning #Bitcoin in an ETF is that liquidity is limited to U.S. market hours. So if the market crashes overnight, you have no ability to sell until the U.S. market opens for trading in the morning. Very frustra…