What are the disadvantages of Coinbase?

Can you elaborate on some of the drawbacks associated with using Coinbase as a cryptocurrency platform? Are there any security concerns that users should be aware of? Additionally, how does Coinbase's fee structure compare to other exchanges, and could this potentially deter some users from adopting the platform? Moreover, is there a limited selection of cryptocurrencies available on Coinbase, or are there plans to expand its offerings in the future? Finally, what are some of the most common customer complaints regarding Coinbase, and how does the company address these issues?