Because crypto in cold storage doesn't earn interest and can't be used as collateral for a margin loan. Crypto is full of people looking for to get rich quick

Because crypto in cold storage doesn't earn interest and can't be used as collateral for a margin loan. Crypto is full of people looking for to get rich quick with interest rates that are obvious ponzi schemes and/or by taking on insane leverage. They don't want to just put tokens in an offline wallet and watch the market prices.