The ATOM is the Cosmos Hub’s primary token and secures the Hub’s valuable interchain services. If you hold ATOM, you can temporarily lock them up to contribute to the security of the Cosmos Hub using a mechanism called Staking. In exchange for locking your ATOM, you receive rewards in newly minted ATOM and a share of the transaction fees that are collected by the blockchain. However, staking is not risk free.
By staking ATOM, you are able to vote in Cosmos Hub governance decisions.