ALGO tokens (the cryptocurrency of Algorand) are used to get the permissionless consensus involved in building a block on the platform and paying for the transaction. In this way, the token helps regulate the ecosystem's growth and rewards those who contribute to governance.
Algorand aims to tackle the blockchain trilemma, which involves decentralisation, scalability and security. In doing so, it relies on randomness and uses proof of stake. The solution is built on a Byzantine agreement, allowing for a consensus even in the presence of bad actors. Pure proof of stake can help achieve higher levels of scalability without compromising security or decentralisation.
To tackle the issues surrounding decentralisation, Algorand ensures that everyone within the system is eligible and nobody knows who the next validator will be, thus helping to ensure security. Staking is used to give every token holder the opportunity to become a block validator.
Within the platform, each user receives a reward in terms of an ALGO token based on their stake for each block committed into the chain. This encourages participation and helps build a path towards decentralisation.