Why UBI is meaningful and critical for the world at large needs no explanation: it provides a certain level of financial stability and therefore guarantees a quality of life that every human being deserves.
What does a nation state really do? Today's nation states simultaneously do a lot and very little. They tend to be very paternalistic and constantly expand scope, all while failing to deliver on the basics — like improving common goods or implementing technology that would benefit everyone.
We are used to the concept of taxes. They were exercised by many entities through history, from feudal lords to modern governments. In principle they don’t differ much from paying for services, given out by someone controlling the land in which activities are carried out.