"Banning retail access to cryptocurrencies is not likely to work," said Menon.
Probably true. But I'd wager that a 1% or 2% transaction tax on cryptocurrency transfers to and from Singapore with a short jail sentence(per transaction) for failure to pay would pretty much eliminate risks of significant economic damage from a crypto crash. If people want to play with this stuff, let them. But you don't want a major chunk of your economy to go to hell if crypto vanishes into a bottomless hole some fine morning.