At one point his digital holdings swelled to $200,000 — around 50 times the average annual income in Vietnam.

But they crashed to zero when the bottom fell out of bitcoin and other cryptocurrencies in recent months.

Getting wiped out “hurt a lot”, he told AFP, but he also learned a valuable lesson: he has come to think of the losses as “tuition fees”.

“When profits were high, everyone became greedy,” said Le, now 23, adding that “it was too good to be true”.

Unlike neighbouring China which has banned cryptocurrencies outright, communist Vietnam has allowed blockchain technology to develop in a legal grey area — barring its use for payments but letting people speculate…