Unless both amounts are zero: zero reasons to pay and zero reasons to receive is a fine solution.
The Job Guarantee at a living wage is a better solution, it's also counter-cyclical and not inflationary (assuming useful work is done, and we have a lot that needs doing).
If I'm missing something here, please tell me.
The first is that the means testing ensures that a small minority of the population receives welfare. If you dissolve the entire apparatus, and distribute the proceeds to all working adults then, in the US, it only comes out to something like $5-6k per year per person. Certainly below the 'living wage' $15/hr = $30k/yr + 'cost of living' adjustments that some are calling for (although this would require almost triple current tax revenues).
The second is that each and every welfare program is the end result of a hard fought political battle, and not a single program will go quietly into the good night. The optics of people suffering due to a particular lost welfare program will receive orders of magnitude more attention than the provision of basic income, no matter how generous. Basic income will become status quo, but sharp recriminations will go on, until at last each and every program will be reestablished. This is more likely the closer the level of basic income is to the $5k "cost saver."