For individuals for whom being unemployed is not an option (e.g. disabled), a negative income tax is a much more humane way of supporting them. For many individuals who could work, a negative income wold create a strong disincentive to seeking paying jobs. While some individuals would chose to do something constructive knowing they could do so without starvation (the proverbial “starving” artist, the kollel person, etc.), many people would choose to goof off and engage in activities such as consuming abusable substances or watching videos, etc.
One should also note that the United States today has a serious labor shortage (especially if the USA tries to restrict Hispanic and other migration and expel illegal aliens), and a negative income tax discourage people from joining the work force.