The linked article mentions cuts in other social welfare programs as one of the risks of a guaranteed basic income. Many who promote guaranteed basic income do not think it should replace our existing programs.
I have never seen anyone advocate for UBI who expressed any position other than support for using it to replace, at a minimum, means-tested poverty support programs, and generally they want it to replace many other targeted social benefit programs that currently provide services, direct subsidies for selected purchases of goods and services, or indirect subsidies through tax credits and deductions for purchases.
The usual argument for UBI is that it eliminates the most of the administrative overhead and duplication of function in the multiple programs it would replace, as well as replacing the perverse incentives that occur with means-testing.