From the perspective that the rich have absolutely designed the government and the tax laws to their own advantage, universal basic income is appealing as an instrument to help balance the scales that have been tipped so far in the wealthy classes' favor to the detriment of other classes. From the perspective that automation is continuing to destroy jobs and more and more industries will be disrupted by it, and full employment is becoming less and less likely in the future, universal basic income is even more appealing. We've seen what happens to countries that have a high degree of permanent unemployment in younger demographics, and they become incredibly violent without much, if any, exception. A program like UBI could alleviate the need for the social security program and all other welfare programs. It would likely make our social programs more efficient while also expanding the economy as it would provide people the economic freedom to create new things. However, the numbers being proposed seem too low at $500 per month to do properly. Finland started a universal basic income experiment in 2017, but sadly I think it has already been abandoned.
Yes, it has been abandoned as it looks like it is not going to do any good to a society at whole. It could make some sense if UBI was paid to everyone, irrespective of the employment status (that is whether you are employed or unemployed) but it would be financially impossible as I come to think. Otherwise, it would do more harm than good as it would discourage people from employment. Really, who would want to work for 1,000 euro a month if you could get 700 euro a month doing nothing? On the other hand, how is this universal basic income different from welfare programs if it is not really universal and not depending on whether you are employed or not?
These are the types of assumptions the experiment was designed to test on a larger scale, so it's disappointing the program is being terminated without adequate data or longevity to satisfactorily provide any useful data on the matter. Such a program wouldn't be financially impossible though, especially if it replaces all current welfare programs. In that sense, the additional spending is quite limited and easily sustainable with a modest tax on the rich or a reduction in other expenditures, say military spending for example. A modest cut in military spending would easily fund the difference, and considering the US spends more on the military than the next 8 or so countries combined, can afford it.
Regarding automation destroying jobs, you should not forget that jobless people won't be able to buy the goods produced by the automated plants, so there should necessarily be a balance between automation and employment. Automation without demand is meaningless (it would only cause overproduction), but demand is not possible without employment.
While true in very general and over-simplified terms, this doesn't pan out much in the real world. The US used to be the manufacturing hub of the world, but when those jobs started getting lost to automation and outsourcing, the US didn't suddenly become a country of poor, unemployed workers. People pursued other opportunities and created new services and products. The difference here is that the loss of manufacturing jobs happened on a decades-long scale, and the displacement of jobs allowed the economy time to absorb the displacement, which happened rather slowly. The difference now is that automation has become so much faster and affected jobs that were previously thought to be immune that there is no clear way for the economy to absorb the loss of millions of jobs in such a short time frame. It will be far more destabilizing now. UBI can help by providing people the basic income to survive and the opportunity to then pursue new products and services, thereby growing the economy, instead of being forced into survival mode and scraping to get by. UBI would never be enough to let people live in the middle class comfortably, just enough to keep people out of destitution.
Also, production comes from demand, not the other way around. You can produce anything, but if there's no demand for the product or services created, the venture will soon fail. When people demand a good or service, you can afford to employ people to provide it, or create it through automation. There is little risk of overproducing anything because the market naturally adjusts price, so it's a problem that solves itself.