I have family in third-world countries, and usually have them buy me flight tickets when I want to visit them. Cheapest way and easiest for them to withdraw, is me sending them USDC. Some of them use USDC directly to exchange with friends for goods and services, others manage to sell them P2P in their country for USD, which they can then trade for local currency.
Messy, inefficient and UX could be way better, but it works and is cheapest for everyone involved.
I have lived and travelled extensively in second and third world countries, and almost never had a problem buying or selling USD. Well, in some places there were indeed capital controls (Argentina, China), but that's rare, and I doubt use of USDC is legal then for the circumvention of regulation (which is basically the only use case of crypto).
If only you know the long queue you have to join now if you want to buy dollars from a Nigerian bank. Not just that you have to fill a form saying what the money is for which had better be one of the things in their list, you have to wait for months to get credited.
Many people visiting countries saying "I have been able to use USD wherever I go, I could even pay for dinners" miss the fact that it's often different for the people who live there, who are gonna have to integrate with the local legal/financial process in order to get their local currency. The tourist hardly have to care about it, and then they tell the internet that there is no problems.
Messy, inefficient and UX could be way better, but it works and is cheapest for everyone involved.