There are a few points that could be made. The primary point is that even though they might score low on some metric, the people of Bhutan are pretty much all well-off and happy. The king decreed democracy not long ago. It's a kind of "existence proof" that people can pretty much be alright.
Consider a couple of other stats from that site:
> the proportion of population with access to electricity in 2020 was 100%.
and a 2.5% unemployment rate.