UBI gives government more control over individuals' finances, especially those without independent means. Poverty is also the result of unfair taxation, where poor people face onerous taxes while receiving less and less in return, and the wealthy avoid tax at every turn. Or that it is difficult for people to be self-employed due to red tape favouring big business. UBI does not address those issues.
UBI also centralises control at the expense of local self-determination and community engagement.