It was a French molecular biologist who became a Buddhist monk and spent 25 years meditating.
They tested his brain with an fMRI machine and found that he was 4 standard deviations above the average when it came to the place in his brain where they suspected happiness stemmed from.
IMO he’s qualified as a happiness expert. Not sure about these writers though.
The western scientific tradition is just starting in this journey (about 50 years of scientific studies exist on people that are considered high meditation achievers).
One of the main ideas of buddhism lacks a good translation, but it is in the fact that understanding something intellectually is NOT the same as understanding something experientially. That's apparent in the way this article is laid out. Just because you have been studying happiness doesn't mean you experience it. This difference in types of knowledge is key, and so foundational at the highest levels of buddhist tantra that working with the intellect is often seen as an impediment. That's why Buddhism is seen as a practice above a religion or philosophy.
But to your point, you are right, looking for transitory moments of happiness is not the same as working towards enlightenment.