If instead you distributed the $billions to every citizen in the country, the vast majority of the money would be spent in local economies on things like day care, car or home repair, taking your kids in for dental cleaning. That is a trickle up economy.
I too reasoned that UBI was liberal social nonsense. But I've been following Andrew Yang's presidential campaign and his justifications make sense from a capitalist point of view. As Yang points out - this is capitalism that doesn't start at zero. It has benefits. Check out his long interviews on Youtube. The Joe Rogan interview is a good place to start https://www.youtube.com/watch?v=cTsEzmFamZ8. If you don't have the time check out his talk with the AARP https://www.youtube.com/watch?v=NXQ3DEFI1eg or the AFL-CIO https://www.youtube.com/watch?v=nlt3nyZdnmI
Or on amazon which is pretty much a front for sending money to China.