> If the idea of UBI is that everyone can sit on their asses and magically get handed money, what even is money at that point?

At that point money is a limit on consumption, so that everyone gets what their fair share of resources, and nobody takes too much.

Those who work in addition to that will receive more, and have a higher standard of living. But everyone should have enough.

At some point AI/AGI might take over the innovation that humans currently do.

People will always create work for themselves, personal and group projects etc but UBI means people would be free to be part of projects just because they want to be, and not because they need the money. But things still work the same as normal in terms of those who want more than the baseline level of luxury that UBI provides.