https://decorrespondent.nl/541/why-we-should-give-free-money...
Either way, whether it's 13% or 5%, it makes us all poorer.
The Namibia experiment is not remotely comparable. That was a) a transfer of wealth from outside the community into it (closer to imperialism than redistribution), b) poverty in Namibia is not remotely like poverty in the US, and c) a big chunk of the BI in Namibia was directed into investment.
The closest analogue of (c) in the US would be funneling money to rich people (who invest) rather than poor people (who consume).