Investing.com - Bitcoin is a fascinating development, but it's not money and as an investment it's highly risky, the head of payment policy at the Reserve Bank of Australia has warned.Tony Richards said there was substantial agreement that bitcoin is not money and while the RBA has been watching them for a number of years, cryptocurrencies do not appear to raise any major concerns for the RBA given their very low use in Australia.Bitcoin and other cryptocurrencies are yet to establish themselves as reliable stores of value, he said.Richards said the various risks of investing in cryptocurrencies are very well summed up by the final words on a page on ASIC's MoneySmart websiteDespite those risks, cryptocurrencies and distributed ledgers are fascinating developments both from a payments and a broader economic perspective, he said.Bitcoin prices have fallen by almost 70% to just over $6,000 from record highs of around $20,000 in December.