From a business economics viewpoint, a relatively new crypto exchange named Cobinhood runs an unstable policy. Their zero fee policy seems nice, but ultimately entails the risk of losing their business - and your money - in the longer term. While more traders on their platform will not bring them more revenue, it will bring them (more) costs. They are totally dependent on the success of their other business activities to keep them in business. Or they can change their zero fee policy for traders.
Probably the zero fee policy is just there to attract a customer base, and did the management team of Cobinhood already plan for a change of the policy later on.