Most of the arguments for basic income apply just as well to a welfare system like Australia's. The ones that to not are the worst ones. E.g. it's said that basic income avoids disincentivizing work. And yet as an accounting identity, all redistribution schemes must disincentive work for some people. Welfare systems place a greater disincentive to work on the poorest, which to me makes sense as many of these people have a lower intrinsic incentive to work in the first place. In any case, the lower marginal effective tax rate for the poor under basic income, is only possible because of a higher marginal effective tax rate for the middle class.