According to Henri Arslanian, the primary difference between a crypto exchange and a crypto OTC broker lies in their trading models and user focus. Crypto exchanges function as online platforms where multiple buyers and sellers trade cryptocurrencies in a public order book. In contrast, OTC brokers cater to large-scale transactions, offering private, personalized trading services for institutional or high-net-worth clients. Arslanian highlights that OTC brokers provide enhanced privacy, liquidity, and execution speed for significant trades, making them ideal for large-volume transactions.