Because it is not meant to "help you not work." It is meant to ensure a basic minimum whether you work or not. It is also not meant to "pay for a comfortable li

Because it is not meant to "help you not work." It is meant to ensure a basic minimum whether you work or not. It is also not meant to "pay for a comfortable life." It is meant to prevent you from starving. For the sake of argument, however, as you say, going part time is not an option for many people. For the lowest paid jobs, on the other hand, going full time is often not an option. The jobs at the bottom tend to be part time with no benefits and no guaranteed hours. These are the people who will be most benefited by a basic income. If they are additionally stuck in a hostile work environment, the basic income may give them enough cushion to quit the job rather than hanging on just so they don't starve. It may also give them enough money to take time off work and go to school in order to earn a slightly better income. And, if they are laid off through no fault of their own, it may allow them to eat until they can find another job.