Hype and FOMO are indeed drivers of growth, but those alone would not explain why rates of crypto adoption are highest in countries with large unbanked populations.
Take a look at this website, which ranks countries by rates of crypto adoption: https://blog.chainalysis.com/reports/2022-global-crypto-adop...
Then compare it to this chart from Statistica, which ranks countries with highest unbanked populations: https://www.statista.com/statistics/1246963/unbanked-populat...
Notice that there is a lot of overlap.
While Bitcoin adoption in countries with strong national currencies like the US or EU is likely driven by FOMO and hype, its main appeal is as an investment/store-of-value for those who lack access to them otherwise, and that is why Bitcoin adoption is highest in unbanked populations.