Older Australians are rushing into buying Bitcoin and other cryptocurrencies to grab a slice of stunning financial returns, but are being urged to tread carefully. Cryptocurrencies are not just attractive to tech-savvy Millennials and younger generations. New data from Australia's largest cryptocurrency exchange, Coinspot, shows almost one in three of its customers are now aged over 40. Crypto craziness continued last week with fresh record highs and US platform Coinbase making its stock exchange debut valued at $110 billion amid wild share price swings. In Australia, Coinspot now has one million customers and its co-founder and CEO, Russell Wilson, says it has noticed a 350 per cent jump in users aged over 40 in the past year, with some aged in their 70s.