Is the payout automatically executed by the blockchain or manually by the customer once I have done my work as a freelancer or reviewer?
Payout it automatic when the task in finalized, or if there is a timeout, the waiting party can finalize as well.
An example: client has 3 days to review work after the freelancer has submitted the solution (accept or start dispute), if not done, freelancer can finalize the task as well, and get the funds.
Payout to reviewers is automatic on finalization in case the task was in dispute.
Nice thing about disputes, and why it is scalable, is that every stakeholder checks off-chain whether they were selected (signing with their private key and checking selection based on their stake), if so then they vote (commitVote), and later only prove on-chain that they were indeed selected (revealVote, more in the whitepaper).