In the Sequoia article, SBF gained his initial funding for FTX from executing trades from the US to Japan, where BTC was overpriced because no one bothered to arbitrage it because of the setup difficulty. The way he did this was by contacting a friend to open a bank account in Japan and manage the funding over there while he managed the account US side.
I am sure some of it is normal corporate shell game but I'd imagine at least 50% of this setup was for regulatory purposes. Even small fintechs will have "shell game like" company structure to please regulatory forces that require having certain things be independent from the consumer platform even if the two companies are working towards the same goal.