But devil's advocate: is there any reason the same outcome couldn't be accomplished with a negative income tax instead, leveraging a bureaucratic infrastructure which already exists and isn't going anywhere?
(US specific) The monthly advanced child tax credit, effectively a negative tax, lifted hundreds of thousands of children out of poverty for the short time it existed. Building that into a permanent, regular, universal cash transfer is not mechanically difficult but is intractable politically.
Of course, I feel obliged to bring up the Georgist objection: that either negative tax or UBI would need to contend with the problem of ground rents, lest landlords simply jack up the rent by the $X additional income that they know for a fact that everyone has.
Fun aside: Thomas Paine, the author of "Common Sense", made one of the earliest proposals for a citizen's dividend [0] (funded by ground rents), but going the other direction: a one-time lump sum during young adulthood, as a means to bootstrap a homestead or small business.