what i cant only understand is your title , why say so when we all need a personal wallet to store our cryptos ? and if not personal wallet , what wallet should we use ? the one that is been shared ? thats risky .
After all it is not rare for exchanges to change their policies and suddenly you find yourself unable to get your coins out of the exchange, and we also need to consider the risk you are incurring by having your coins there when we know that hackers are always trying to gain access to exchanges and many times in the past they have been successful and have stole fortunes from them.