Why USDT works for hosting in Senegal
USDT holds its dollar value, so the invoice never drifts between the quote and the transfer. In Senegal the alternative is a card billed in dollars against a West African CFA franc (XOF) balance. Local cards settle in XOF, so any foreign-transaction fee on a dollar invoice comes from the issuing bank.
Paying from a wallet takes the bank out of the transaction. The invoice is priced in US dollars, the USDT amount is locked for 15 minutes at the live rate, and the transfer goes straight to the address on the invoice. Nothing to approve, no merchant category to argue about.