When fiat currency is placed in a certificate of deposit in a bank then the bank lends out that capital to create economic activity. When Hex is staked then what economic activity happens?
Nothing, and you get more tokens after they hold it for a certain time.
staking is generally to keep the network running and growing so when you deposit some money here you are helping the network itself to remain stable
Please correct me if I am wrong

Staking is more to keep coin owners to sell their coins, so that there's more buyer pressure, but once the stake is off, you get more coins and suddenly, there's more sell pressure.