Crypto OTC desks use USDC for three main reasons: as trading capital, as a quote currency, and as a counterparty settlement instrument.

Prior to the emergence of stablecoins, crypto traders who preferred to remain in crypto used BTC as their quote currency. Due to the volatility of bitcoin, this was not ideal for professional traders. Alternatively, traders could trade fiat-to-crypto by linking up their bank accounts to exchanges but slow wire transfers were a persistent issue for traders.

Today, thanks to stablecoins, traders have the ability to move in and out crypto using fiat currency in tokenized form. Fiat-backed stablecoins like USDC function similarly to cash, but with added flexibility. For OTC desks (and their customers), that means USDC is an extremely effective quote currency to use for trading.