Hong Kong and Macau are Special Administration Regions of China. When they were absorbed into China, the PRC government didn't want to collapse the local economies. They knew they had a good thing going there so they gave them significant autonomy. Hong Kong has it's own customs and border controls, as well. You don't need a Chinese visa to visit Hong Kong. And the government was largely very autonomous, too, though recent efforts by Beijing to meddle in local politics have been the cause of large protests.
I've still got a few old HK dollars with the Queen on the back from when I lived there before 1997. She's gone now, but the currency has endured. Despite Beijing's steady encroachment that Kalbahamut mentioned, for the most part HK and Macau function as independent states. HK's Basic Law is essentially it's own mini-constitution and it maintains its own border controls, and, as mentioned, currency. Additionally it fields its own teams in many sporting competitions. Identity is a tricky thing in HK, but at least when I was there last (a while ago now - not since about 2008) they thought of themselves as HKers first and Chinese very much second.
Basic Law is the constitution of Hong Kong, but Beijing holds the right of interpretation of it (which means it can have the authority to change the law), and it has been done 6 times ever since its handover in 1997. I am born and raised in Hong Kong (even when I am typing this right now), I believe Hong Kong is a fully autonomous region, yet its commercially and socially free state is gradually undermined by Beijing, which is a very saddening fact to be note.
Speaking of the Hong Kong dollar (as well as the Macau dollar), our colonial government (the UK for Hong Kong and Portugal for Macau), had given a great financial status as mentioned by kalbahamut, so the Chinese government want to maintain it as to keep it prosperous.
34/35 is beating 91.7% now, so maybe the pool of hardcore quizzers who took the quiz the moment it was featured is being diluted by the casuals who just happened to notice it in passing and thought they'd give it a go, sort of like how the hyperfans are always at the premiere of a film, and after a few weeks when it's about to end, the stragglers kind of find their way into the cinema to check it out. This quiz is the quiz equivalent of films.
The value of these currencies are almost all pegged to or at least closely related to the value of the US dollar because, since the oil industry began in Pennsylvania and has been dominated by the US ever since (formerly in supply, currently in demand)- the price of a barrel of oil has always been in US dollars. So... these countries do almost all of their relevant business in US dollars. The local currencies are just that: local. I know from first hand experience taking a lot of Saudi riyals overseas somewhere and trying to exchange them is a horrible idea and you'll take a big loss because nobody wants riyals. Much better to convert to USD in Saudi first, and then exchange the dollars upon arrival. The only time these currencies are traded is when Saudis go to neighboring GCC countries and vice versa, but those neighboring countries are all tiny so this doesn't amount to much.
Though that being said I am a bit surprised that the krona, krone, and New Zealand dollar are higher than the riyal. That seems weird. I guess the first two because the economies of Europe are so closely intertwined... but the last one seems inexplicable to me.
Neither of those seem to be good explanations to me. Thailand receives waaay more tourists than New Zealand does and the Thai baht isn't on here. And there are many countries with significantly larger economies, or that are by various metrics wealthier and/or growing faster, also not represented.
The quiz is about currencies, not about sovereign countries. Plenty of places that aren't countries issue their own currencies (e.g. Isle of Man, Jersey, the town of Lewes in England).
Call what the dollarzone? There's no such thing. As opposed to the Eurozone, which is a thing. The EU is not Europe. Not all countries in the EU use the Euro. And some countries not in the EU belong in the Eurozone. The group of countries that use the Euro are called the Eurozone, though there are other countries (Kosovo, Montenegro) that use the Euro that are not part of the Eurozone, just like there are other countries that use US dollars that are not part of the United States.
Bitcoin? Gold? Please update -- would also be interested to know where the Ruble is post-Ukraine invasion sanctions? Probably off the chart, with gains to rupee and yuan?
Gold is more of a commodity than an actual currency. Unless you're referring to Zimbabwe Gold, which definitely pales in comparison to the currencies listed.
Speaking of the Hong Kong dollar (as well as the Macau dollar), our colonial government (the UK for Hong Kong and Portugal for Macau), had given a great financial status as mentioned by kalbahamut, so the Chinese government want to maintain it as to keep it prosperous.
Actually, the fact that the yuan is placed in 9th surprises me (in my opinion, too low for that economy)