If we talk about security, then I would not advise you to keep all your coins on the exchange, because you can leave a certain amount there to trade, and the rest is transferred to a protected wallet
There have been many posts relating to this question, and in agreement with most of the people on here, its best to keep it off the platforms. Its way safer in your own private wallet then anywhere else, that I can think of, excluding nanoS.
maybe other people think if tehy save in market,they can trade it whenever they want. can't force them only suggestion, but as long they already put strong security on their account. just let exchanger to manage the rest of it