A few months ago, I heard or read somewhere over the internet that some institutional investors keep their funds in the exchange where they buy them, I think the reason was that they believe exchanges are safer than wallets but that isn't true in all cases because exchanges have higher odds of getting attacked by hackers so there can be negative consequences of doing that.
Reasons that are not based at all. I think they have a certain time to maintain their funds in the exchange because they also realize the risks that will be received if they continue to maintain a sum of money in the exchange.
Only investors do not know anything ready to lose some money. Maybe they only see convenience such as no need to pay shipping costs if the money is left stored on the exchange.
No matter how great the stock exchange and no matter how big the trust of a stock exchange, it's still not a good choice to save money online because the exchanges and cold wallets are two things that have a very large difference in function.