The rationale is explained by Alan Sheahen:
Job creation is a completely wrong approach because the world doesn’t need everyone to have a job in order to produce what is needed for us to live a decent, comfortable life. We need to re-think the whole concept of having a job. When we say we need more jobs, what we really mean is we need is more money to live on.
One answer is to establish a basic income guarantee (BIG), enough at least to get by on — just above the poverty level — for everyone. Each of us could then try to find work to earn more. A basic income would provide economic freedom and income security to everyone. We’d have the freedom to work less if we wanted to, or work the same amount and save or spend that money. It would provide a direct stimulus to the economy, which would help create more jobs.