Disclaimer: For most of my career I've been paid in USD, but never in crypto. I'm not a fan of it, but I'm not too blind to see why my peers are using it.

> Why would they want to pay them in USD and not the local currency?

To be blunt, because the local currency is useless. You're presumably from somewhere in the Western world, so smack dab in the very first-world bubble being discussed here where "fiat" means stability and not simply a measure of an economy in free fall. Outside of the world's strongest economies there is very real incentive for individuals and businesses alike to hold currencies that don't lose significant amounts of their value from month to month. I started at my current role in April 2021 at which point the parallel market exchange rate was ₦480 to $1; earlier this month I exchanged currencies at ₦600 to $1. Less than a decade ago in 2014/15 the pm exchange rate was ₦200 to $1. Why on earth, if I had a choice, would I take a salary pegged to the naira in such conditions?

People in the first world also vastly overestimate how useful holding [local] fiat is in the global market. Sure when your currency underpins the global economy you never have to think about foreign exchange, but for most developing countries pretty much no international marketplaces will take your local money. They may show localised prices but the actual transactions are settled in USD (or similar), which is often harshly controlled. For example naira-denominated Mastercards and Visa cards here have international spending limits - currently those limits are as low as $20 a month (not an exaggeration or typo) from major banks in the country. Middle-class people resort to using virtual dollar card services (which charge exorbitant rates, and which are often detected/blocked by platforms) to be able to pay for basic subscriptions. And for bigger expenses, getting large amounts of foreign currency ($1000+) from local currency involves either filing a Form A with the central bank (you get dollars at the official exchange rate, but the process takes a month or more, must be for an approved purpose, and again has spending limits - if you want to travel for tourism/business you can request a maximum of $4000, if you're attending a foreign university you can request a maximum of $15000 for tuition and $5000 for living expenses per semester, etc) or doing quasi-legal transactions at bureau de changes that are charged at the parallel market rate.

Whether or not you consider those limits too frugal, I personally am not interested in the government restricting me from spending literally my own money. So I simply receive and hold my salary in foreign currency and exchange a fraction of it to the naira for day-to-day living expenses. All my international transactions - new electronics, flight tickets, etc - I pay for directly. If I want to send money to friends or family outside the country I can do that without fuss. I'm able to receive USD directly because I have a foreign currency account and restrictions on the foreign exchange of the naira don't apply to it obviously. Not everyone can get one (e.g. most banks require you to present two references who themselves have FCAs to qualify), so they turn to alternatives like Payoneer and Wise. But those charge significant fees to make profit and will ban/block accounts especially of people from the developing world on a hair trigger (and also recent government controls mean that you can no longer withdraw from those accounts to a local naira account, so getting cash for local expenses is an issue), so recently people are increasingly turning to cryptocurrencies as well.

You need to understand that in a failing economy, crypto is just another foreign currency - one that is in some ways easier to obtain and hold safely (under a government that can and will freeze your bank account for dissident activity) than traditional foreign currencies. It's volatile, but averaged over time it's certainly held its value significantly better than the naira ever has. It's a gamble, but people don't have the luxury of caring as strongly about the risk as those who can comfortably rely on their own fiat. I consider myself lucky that I've been able to avoid using it; I don't judge those that have.

> What was preventing them from official employment?

You cannot officially employ people in a jurisdiction you do not operate in.

For all HN talks about remote work and hiring all over the world, how exactly do you imagine that works out legally? My employer certainly considers me a full-time employee in spirit (and so do I), but the paperwork is quite clear that I'm an independent contractor - same for all my non-American colleagues.