This map is somewhay misleading, some countries use currency without decimals, making their currency worth effectively less. Take for example the euro, a cent (a one hundredth of an euro) is cerntainly worth less than a robux while an euro isn't. The same comparison with the japanese yen (efectively a cent) shows that robux is more valuable. The map should be how many robux can you buy with the minimum wage for example.
Yeah currency will have a whole unit. Common purchases may or may not fall within the range where that unit is the order of magnitude to think of, much in the same way the meter may or may not be the order of magnitude you think of, but it is the 1 marker. Cents are portions of the dollar, yen are whole 1s, even though they’re more or less comparable. Euro-American currencies tend to be subdivided into hundreds, and if needed fractions from there such as the halfpenny.
The point of the comment is to point out the common misconception that the value of one [token of a currency] has anything to do with the strength of a currency. As described in the comment, the value of a singular token of a currency can be chosen arbitrarily.
This, of course, doesn't mean the map is factually incorrect.
But the value of a unit of currency being unrelated to the currency's strength had nothing to do with whether that currency has cents or not. That comment just used the wrong explanation to make a correct point.
Also the map isn't entirely useless, because what it does illustrate is currencies which likely suffered from high or hyper-inflation in the past (or are very old). Obviously, no government first issues a currency and says "... and so one loaf of bread is 10000 schmeckles". That's just impractical.
Of course this doesn't mean that then Japanese Yen is a bad currency, but it does make for an interesting historical point.