What is a Coinbase Exchange?

Could you please elaborate on what a Coinbase Exchange is and its significance in the cryptocurrency and finance world? As a professional practitioner in this field, I'm curious to understand its functionality, how it differs from other exchanges, and what role it plays in facilitating cryptocurrency transactions. I'm particularly interested in its reputation for security and user-friendliness, as well as any recent developments or expansions that Coinbase Exchange has undergone. Your insights would be invaluable for those seeking to navigate the cryptocurrency landscape.