What are the odds that they've exposed the personal information of thousands of airport travellers who have exchanged foreign currencies with them?
That said, there has been news of late that these kinds of attacks are indeed stepping up the value chain of stealing, selling, mining the data itself. But I would tend to think not, in this case, as the ransom note would have been much more severe.
But the article says all computer systems are off which is clearly not the case so who knows...
Anyone who pays the terrible airport rates for large conversions is probably laundering money.
Literally every other option is better.