Earlier quoted context omitted.
I too think a negative income tax is a better method, but UBI is at least testable in some form. I think we'll see UBI tested and if successful, a negative income tax will be more politically feasible than UBI.
A negative income tax requires the same sort of bureaucracy from our current means-tested welfare systems, whereas a simple UBI paid to all does not.
With UBI, it is possible to have it paid by entity other than government, but that's a different story.