4 or 5 years ago some pretty influential books were published on UBI, automation, post-work, etc. i would hardly call it 'immature', the idea has been around in reports, conferences, papers and commentary/discourse generally for decades.
using it because of covid and stipulating measures such as spending locally and not on tax-avoiding multinationals is indeed a great idea. but seems like such UBI schemes are going to become more and more justified, especially in a country where 15-20% of all labour is automated by robots. the 'retrain as a coder' line just doesn't work for 20% of the total workforce. and the alternative, as we have seen in rust-belts all across europe and america, is workers turning increasingly to populist demagogues to express their fears and anger.
of course for UBI you need a pretty strong state and for things like taxation of the mega-rich/corporations to be a relative non-issue.