Take this article with a grain of salt as it comes from a left-leaning publication, interesting nonetheless. They link to another article saying only 2% of remittances are coming in via BTC.

"Despite a reported $425 million spent by the Salvadoran government, the bitcoin project has not gone according to plan: After a botched rollout, bitcoin adoption is exceedingly low. The vast majority of merchants prefer cash, not only because it’s easier to make transactions, but also because many of them don’t understand how cryptocurrency functions, the bitcoin point-of-sale systems don’t always work, or they have no internet access."

Fritz Haber of the "Haber-Bosch synthesis" won the Nobel Prize for this discovery and is also the father of chemical warfare. His work led to the development of Zyklon B used in the gas chambers during WWII.

The Population Bomb is a 1968 book written by Stanford University Professor Paul R. Ehrlich and his wife, Anne Ehrlich. It predicted worldwide famine in the 1970s and 1980s due to overpopulation, as well as other major societal upheavals, and advocated immediate action to limit population growth. Fears of a "population explosion" existed in the 1950s and 1960s, but the book and its author brought the idea to an even wider audience.

The book has been criticized since its publication for its alarmist tone, and in recent decades for its inaccurate predictions.

According to this article they used their own BTC, NOT users':