Huh, how are they a middleman? You mean between individuals trading (GDAX) or between cryptocurrency and fiat currency (the main Coinbase.com product)? Neither

Huh, how are they a middleman? You mean between individuals trading (GDAX) or between cryptocurrency and fiat currency (the main Coinbase.com product)? Neither of those services are what I would call a “middleman,” and neither of them are “supposed” to not exist in the cryptocurrency market (with the exception of some proposals to create fully decentralized exchanges).