That job guarantees exceptionally produce useful things doesn't mean that they don't overwhelmingly produce useless things, or things that are more expensive than they're worth.

> doesn't mean that they don't overwhelmingly produce useless things, or things that are more expensive than they're worth

One could say the same thing about all the little art projects a hypothetical society on UBI might busy itself making. The pertinent difference seems to be one about scale and co-ordination. Job guarantees say we work together–through a centralised power–to build big things. Handing everyone cash leans more towards arts and crafts and consumption.