When you seriously come to think about it - storing your Crypto in exchanges is better than using cold wallets.
Looks like you was booze-fueled when wrote that. Say this face-to-face to customers who experienced disasters of Mt.Gox-grade. Cold wallets under personal control are the safest places where private keys for crypto can be stored, hardware wallets follow. Exchanges must be considered as the spots for trading and/or conversion rather than for storing.