According to the Asia Development Bank 8.2% of the population lives below the poverty line, was your point that this is a low percentage?
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.
For concreteness, I'll say that I would define "poor" as not having the capability to satisfy the lower tiers of Maslow's hierarchy. ( https://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs ) By that standard Bhutan isn't poor despite being technically a Third World nation.