There are many exchanges we do not feel comfortable using for a variety of reasons, including high trading fees, high withdrawal fees, clunky interfaces, lack of regulatory oversight, white label sites, and sites based in China (where the government periodically threatens to ban cryptos — you do not want funds on a Chinese exchange on that day).
The only good reason not to use Coinbase or Binance is if they do not list the coin you are interested in. In that case, research is needed to find the best alternative. If you want us to do that research for you, please let us know.
We believe it is best to avoid any exchange not listed in Module 3.9.
Please feel free to contact us with any questions.