As a welfare replacement, it is much more efficient, since there is no effort spent determining who qualifies. People can spent their money however they want, rather than the patchwork of separate programs we have now.
It doesn't need to bring anyone down. It's just a different way of distributing what we already receive. For you ordinary workers, they will receive $X in a monthly check, and their salary can be reduced by $X (since the minimum wage can also be abolished).
That does mean that the desirability of some jobs will shift. Good. We have a bunch of very dirty jobs being done for minimum wage, even though demand is extremely high. I'd love to see the garbage men and chicken processors get more money for their dangerous work.
And if I get less for my cushy desk job, oh well. Especially since we seem to be putting all of the effort into replacing me, and none into the jobs that come with hazards to life and limb.