Bitcoin ([^BTCUSD](https://www.barchart.com/crypto/quotes/%5EBTCUSD/overview)) tumbled to a 7-week low today and has slumped more than -20% since spiking to a 2-year high on January 11 when the SEC finally approved spot Bitcoin ETFs. However, the cryptocurrency market has reacted in a buy-the-rumor-sell-the-fact mode since then as the big surge into cryptocurrencies failed to materialize following the SEC approval, and speculators have become more cautious about the potential impact of the products. Bloomberg Intelligence said a net $1.1 billion flowed into the newly approved Bitcoin ETF funds…