How markets in the poorest of countries revolve around circular markets working on about $1/day. How can these people use bitcoin non custodially when each transaction they make on chain would cost them 1/5 of their daily income? If fees ever go above 1 sat/vbyte, I would find it very hard to convince any of these people to use bitcoin. Every solution I can think of involves at least one on chain transaction or custodial solutions.
Most of these countries have a designated local exchange where they can store their BTCs. Unfortunately, however, exchanges are NOT secured when it comes to storing our BTCs given that they do not have full custody over their private keys.
I do suspect that people in these countries exchange their BTCs for their equivalent local currency for their disposal. While for others, I do think they purchase a hardware wallet for safely storekeeping their BTCs.