{video} A top U.S. central banker warned Monday that investors should be careful when investing in cryptocurrencies. Federal Reserve Bank of St. Louis President James Bullard said Monday that crypto assets have a use case for facilitating transactions that are difficult to make with fiat currencies. But he suggested that there may be too many types of private cryptocurrency projects out there. “We have a couple of thousand of these around, most of them are worthless,” Bullard told Yahoo Finance in an exclusive interview. Bullard’s remarks come as crypto markets continue to teeter. At the worst point during this past ... (full story)